Note: Descriptions are shown in the official language in which they were submitted.
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COMPRESSION APPARATUS
BACKGROUND
1. Technical Field
The present disclosure generally relates to the field of vascular therapy for
application to a limb of a body, and more particularly, to a compression
apparatus
configured to artificially stimulate blood vessels, of the limb.
2. Description of the Related Art
A major concern for immobile patients and persons alike are medical conditions
that
form clots in the blood, such as, deep vein thrombosis (DVT) and peripheral
edema. Such
patients and persons include those undergoing surgery, anesthesia and extended
periods of
bed rest. These blood clotting conditions generally occur in the deep veins of
the lower
extremities and/or pelvis. These veins, such as the iliac, femoral, popiteal
and tibial return
deoxygenated to the heart. For example, when blood circulation in these veins
is retarded
due to illness, injury or inactivity, there is a tendency for blood to
accumulate or pool. A
static pool of blood is ideal for clot formations. A major risk associated
with this condition
is interference witli cardiovascular circulation. Most seriously, a fragment
of the blood clot
can break loose and migrate. A pulmonary emboli can form blocking a main
pulmonary
artery, which may be life threatening.
The conditions and resulting risks associated with patient immobility may be
controlled or alleviated by applying intermittent pressure to a patient's
limb, such as, for
example, portions of a leg and foot to assist in blood circulation. Known
devices have been
employed to assist in blood circulation, such as, one piece pads and
compression boots. See,
for example, U.S. Patent Nos. 4,696,289 and 5,989,204.
Compression devices that consist of an air pump connected to a disposable
wraparound pad by one or more air tubes have- been used. The wraparound pad is
placed
around the patient's foot or other extremity. Air is then forced into the
wraparound pad
creating pressure around the parts of the foot or other extremity.
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These known devices may suffer from various drawbacks due to their bulk,
cumbersome nature of use, potential for contamination and irritation to the
extremity
during application and use. These drawbacks reduce comfort, compliance, cause
skin
breakdown and may disadvantageously prevent mobility of the patient as
recovery
progresses after surgery.
Therefore, it would be desirable to overcome the disadvantages and drawbacks
of
the prior art with a foot sleeve that prevents contamination, mitigates the
incidence of skin
breakdown and facilitates disposal with an extremity. It is contemplated that
a
compression apparatus including the foot sleeve reduces bulk and is not
cumbersome
during use to improve comfort and compliance to a patient. It is further
contemplated that
the compression apparatus is easily and efficiently manufactured.
SUMMARY
Accordingly, a compression apparatus is provided that prevents contamination,
mitigates the incidence of skin breakdown and facilitates disposal with an
extremity for
overcoming the disadvantages and drawbacks of the prior art. Desirably, a
compression
apparatus including the foot sleeve reduces bulk and is not cumbersome during
use to
improve comfort and compliance to a patient. The compression apparatus is
easily and
efficiently fabricated.
The compression apparatus, according to the present disclosure, are configured
to
provide vascular therapy, including for example the prevention of deep vein
thrombosis
("DVT") by artificially stimulating blood vessels throughout the foot of a
patient,
including the toes and the heel, to increase blood circulation for patients.
The compression
apparatus according to the present disclosure is an intermittent pneumatic
compression
device for applying slow compression to a foot. Such pressure simulates blood
flow that
would normally result from, for example, walking, by employing a foot sleeve
that is
supported about a foot of a patient.
The compression apparatus may have an inflatable bladder designed to cover and
engage the entire area of the bottom of the foot, beyond the heel and ball to
a substantial
portion of the toes. The inflatable bladder wraps about the side portions of
the foot via a
hook and loop type connector flap that transverses the instep of the foot.
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The inflatable bladder may include an outside layer and an inside layer. The
bladder
can be formed by welding the outside layer and the inside layer together. The
bladder
provides a uniform application of pressure to the entire foot and is then
deflated. Moreover,
the compression apparatus may include bladder sections that are capable of
enabling venous
refill detection. The compression apparatus according to the present
disclosure includes
various embodiments and combinations as will be appreciated herein. The
various
embodiments and coinbinations may each be manufactured in various sizes to
accommodate
subjects of varying sizes as well as right and left foot models.
The compression apparatus includes a strap that improves comfort by using a
single
piece laminate structure whose inside layer is a cushioning layer. The strap
is integrated
with a foot sleeve by sandwiching the strap between separate layers of the
foot sleeve body.
The comfort to the patient may be improved by segmenting the strap to contour
about the
heel of the foot. The strap can also include one or more layers configured to
provide a
barrier to the cushioning layer from the environment. The foot sleeve can
iinprove ease of
use by having a universal design with a one flap metatarsal closure.
The strap may include a laminate consisting of various layers. The layers may
include a center layer that is configured for comfort. Outside layers disposed
about the
center layer provide a barrier between the environment and an outer surface of
the foot.
One of the outside layers can be a skin contact layer that is soft to the
touch. The strap may
be a separate part integrated into the body of the foot sleeve by being
sandwiched between
separate layers of the foot sleeve body and then permanently secured. The body
of the foot
sleeve may be designed for adaptability to various foot sizes and shapes by
employing a
single metatarsal flap that facilitates ease of use. The body may be
configured to provide
inspection of the tops of the phalanges of the foot.
One of the advantages of the present disclosure is a cushioning layer that is
not in
direct engagement with the outer surface of the foot. The cushioning layer has
a soft skin
contact layer. The foot sleeve may also include a liner that is configured to
provide a
physical barrier to the cushioning layer that assists in the prevention of
contamination. The
interior cushioning layer provides comfort and mitigates skin breakdown. Thus,
the foot
sleeve improves patient compliance and provides sanitation by isolating the
cushioning
layer from the environment.
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The foot sleeve is also easily manufactured, for instance, the material stack
up
contained in the layers allows the strap and/or foot sleeve to be cut as one
piece and
ensures an even stack up of materials.
In one aspect, in accordance with the principles of the present disclosure,
the
compression apparatus includes an expandable body configured for disposal
about a
foot. A strap extends from the body. The strap is configured for disposal
about the foot
adjacent an ankle. The strap has a first layer configured to engage an outer
surface of
the foot adjacent the ankle, a second layer and a third cushion layer disposed
therebetween.
The strap may be integrally connected to the expandable body. Alternatively,
the strap may be monolithically formed with the expandable body. The
expandable
body can include a first, top layer and/or a second, bottom layer. Moreover, a
portion of
the strap member may be disposed between a top and bottom layer of the foot
sleeve
body. The strap may have a segmented configuration for contour with the foot.
The
third cushion layer can be disposed within the first layer and the second
layer such that
the first layer and the second layer are configured to provide a barrier to
the third
cushion layer. The body can include a metatarsal strap.
Alternatively, the first layer includes a soft polyester material. The first
layer
may include a soft polyester material and polyvinylehloride. The third cushion
layer
may include a foam material. The second layer can have an outer surface
including a
loop material disposed therewith. The second layer may include a
polyvinylchloride
material and an outer surface having a loop material disposed therewith.
Alternatively,
the second layer has an outer surface including a loop material such that the
metatarsal
strap includes hook elements that are engageable with the loop material to
mount the
compression apparatus with the foot. The body may include hook elements that
are
engageable with the loop material to mount the compression apparatus with the
foot.
In an alternate aspect, the compression apparatus has a foot sleeve including
an
inflatable body configured for disposal about a foot. The foot sleeve includes
a
metatarsal portion. A strap is integrally connected to the foot sleeve and
extends
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therefrom. The strap is configured for disposal about the foot adjacent an
ankle. The
strap has a first layer configured to engage an outer surface of the foot
adjacent the
ankle, a second layer and a third cushion layer is disposed therebetween. The
first layer
and the second layer are configured to provide a barrier to the third cushion
layer. The
first layer may be configured to prevent engagement of the third cushion layer
with the
outer surface of the foot.
In another aspect, there is provided a compression apparatus comprising: a
foot
sleeve including an inflatable body configured for disposal about a foot, the
foot sleeve
including a metatarsal portion; the foot sleeve further having a contact layer
and an
outer layer, the layers fixedly joined at a perimeter of the foot sleeve
defining a first
piece; a heel strap comprising a first layer and a second layer fixedly joined
at a
perimeter of the first and second layer, and a third layer between the first
and second
layer and the three layers defining a second piece; and wherein a portion of
the second
piece is received within the first piece between the contact layer and outer
layer at the
perimeter of the first piece, and the second piece is fixedly joined at the
perimeter of
the first piece, the second piece projects out through the sealed first piece
at its
perimeter and extends a substantial length outwardly therefrom for wrapping
over and
around the foot adjacent an ankle of a patient.
BRIEF DESCRIPTION OF THE DRAWINGS
The objects and features of the present disclosure, which are believed to be
novel, are set forth with particularity in the appended claims. The present
disclosure,
both as to its organization and manner of operation, together with further
objectives and
advantages, may be best understood by reference to the following description,
taken in
connection with the accompanying drawings, which are described below.
FIG. 1 is a plan view of one particular embodiment of a compression apparatus
and showing an inflatable bladder and a foot in phantom, in accordance with
the
principles of the present disclosure;
FIG. lA is a partial cross-sectional view of the compression apparatus shown
in
FIG. 1;
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FIG. 2 is a cutaway cross section view of a strap of the compression apparatus
shown in FIG. 1;
FIG. 3 is a cutaway cross section view of an alternate embodiment of the strap
of the compression apparatus shown in FIG. 1;
FIG. 4 is a plan view of an alternate embodiment of the compression apparatus
shown in FIG. 1, illustrating an inflatable bladder in phantom;
FIG. 5 is a plan view of another alternate embodiment of the compression
apparatus shown in FIG. 1, illustrating an inflatable bladder in phantom;
FIG. 6 is a plan view of another alternate embodiment of the compression
apparatus shown in FIG. 1, illustrating an inflatable bladder in phantom; and
FIG. 7 is a plan view of another alternate embodiment of the compression
apparatus shown in FIG. 1, illustrating an inflatable bladder in phantom.
DETAILED DESCRIPTION OF EXLEMPLARY EMBODIMENTS
The exemplary embodiments of the compression apparatus including the foot
sleeve and methods of operation disclosed are discussed in terms of vascular
therapy
including a compression apparatus for application to a foot or other limb of a
body and
more particularly in terms of a compression apparatus configured to
artificially
stimulate the blood vessels of the limb including the foot, heel and toes of a
patient. It
is contemplated that the compression apparatus may be employed for preventing
and
overcoming the risks associated with patient immobility. It is further
contemplated that
the compression apparatus alleviates the conditions arising from patient
immobility to
prevent for example, DVT, and peripheral edema. It is contemplated that the
compression apparatus according to the present disclosure may be employed with
various types of venous compression systems, including, but not limited to
rapid
inflation, slow compression, non-sequential and sequential compression
apparatus. It is
envisioned that the present disclosure, however, finds application with a wide
variety of
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immobile conditions of persons and patients alike, such as, for example, those
undergoing surgery, anesthesia, extended periods of bed rest, obesity,
advanced age,
malignancy, and prior thromboembolism.
In the discussion that follows, the term "subject" refers to a patient
undergoing
vascular therapy using the compression apparatus. The following discussion
includes a
description of the compression apparatus, followed by a description of an
exemplary
method of operating the compression apparatus in accordance with the
principals of the
present disclosure. Reference will now be made in detail to the exemplary
embodiments and disclosure, which are illustrated with the accompanying
figures.
Turning now to the figures, wherein like components are designated by like
reference numerals throughout the several views. Referring initially to FIGS.
1, 1A and
2, there is illustrated a compression apparatus 10, constructed in accordance
with the
principals of the present disclosure (see, for example, the compression sleeve
described
in published U.S. Patent Application No. 20050187503, filed on February 23,
2004 and
entitled Compression Apparatus). Compression apparatus 10 includes an
expandable
body, such as, for example, a foot sleeve 12 configured for disposal about a
foot F of a
subject (not shown). Foot sleeve 12 may be disposed with the right or left
foot of the
subject. Foot sleeve 12 fluidly communicates with a pressurized fluid source
14 via
tubing 16 and a valve connector 18 (see, for example, the valve connector
described in
published U.S. Patent Application No. 20050184264, filed on February 23, 2004
and
entitled Fluid Conduit Connector Apparatus) for applying compression to the
left foot
and/or the right foot to provide vascular therapy to the subject and augment
venous
return. Compression apparatus 10 employs a controller 20 to regulate fluid
pressure for
vascular therapy. See, for example, the controller described in U.S. Patent
Application
Serial No. 10/784,323, filed on February 23, 2004 and entitled Compression
Treatment
System, the entire contents of which is hereby incorporated by reference
herein.
Pressurized fluid source 14 may include a pump and may be stationary or
portable. It is
contemplated that pressurized fluid source 14 may include the necessary
electronics
and computer software to carry out vascular therapy, in accordance with the
principles
of the present disclosure.
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Foot sleeve 12 is configured to apply vascular therapy to the entire area of
the
bottom of foot F, beyond a heel H and a ball B to a substantial portion of
toes T. It is
contemplated that foot sleeve 12 and other parts of compression apparatus 10
may be
disposed, wrapped and mounted with various limbs and extremities of a
subject's body,
such as, for example, legs and arms. It is further contemplated that foot
sleeve 12 or
portions thereof may be disposable. It is envisioned that foot sleeve 12 may
include
flexible sections, such as, elastic or spandex materials to facilitate
mobility of a limb
during use. The components of strap 22 may be fabricated from materials
suitable for
compression vascular therapy such as, for example, fihns and fabrics, such as
PVC
(polyvinyl chloride) and PE (polyethylene).
Strap 22 is configured for disposal about foot F adjacent to the ankle. Strap
22 is
integrally connected to foot sleeve 12 and fixedly mounted between a foot
contact layer
26 and an outer layer 28 of foot sleeve 12, as will be discussed. Strap 22 may
be
monolithically formed with foot sleeve 12, wherein at least a portion of the
strap 22 is
formed from the same contiguous material as a portion of the foot sleeve 12.
By way of
non-limiting example, foot contact layer 26 may be formed from the same
contiguous
material as foot contact layer 32 of foot sleeve 12. Strap 22 has segmented
portions 24
that are configured to contour about heel H of foot F. It is contemplated that
segmented
portions
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24 may be variously configured and dimensioned, such as, rounded or
alternatively, strap 22
may have a uniform outer surface, such as, smooth.
Strap 22 has a first layer, such as, for example, foot contact layer 26 that
is
configured to engage to an outer surface of foot F adjacent the ankle. Foot
contact layer 26
includes a soft polyester material 26a that is soft for engaging the skin of
the subject. This
soft skin contact layer 26 advantageously provides comfort to the subject,
prevents
contamination and mitigates skin breakdown. Foot contact layer 26 may also
include a
PVC portion 26b disposed adjacent soft polyester material 26a.
A second layer, such as, for example, outer layer 28 cooperates with foot
contact
layer 26 such that a third layer 30 is disposed therebetween. Third layer 30
includes a foam
material to provide a cushioning effect to the subject. It is contemplated
that layer 30 may
include alternative materials that provide a cushioned configuration. Outer
layer 28
includes a loop type materia128a disposed therewith, for engagement with a
corresponding
hook element of foot sleeve 12, and a PVC portion 28b disposed adjacent loop
material 28a.
Outer layer 28 advantageously prevents contamination of third cushion layer 30
from the
environment, such as, for example, air, moisture and dirt.
Foot contact layer 26 and outer layer 28 are configured to form a physical
barrier to
third cushion layer 30. This configuration advantageously provides comfort to
the subject,
as well as compliance, and prevents contamination of third cushioning layer
30. In an
alternate embodiment, as shown in FIG. 3, strap 22 includes a laminate
structure having a
cushion layer 130 and a PVC portion 132 disposed adjacent thereto. An outer
layer 134 is
disposed adjacent PVC portion 132. Layer 134 may include a soft polyester
material for
engaging the outer surface of foot F, or alternatively, may include a loop
material to prevent
contamination of cushion layer 130 from the environment.
Foot contact layer 26 and outer layer 28 are overlaid to form strap 22. Foot
contact
layer 26 and outer layer 28 are fixedly joined at seams adjacent corresponding
perimeters
thereof, to support the components of strap 22. The components of strap 22 may
be bonded
via welding, e.g., RF welding, adhesive, industrial strength double sided tape
and the like.
It is envisioned that only a portion of the foot contact layer 26 and outer
layer 28 are joined.
It is further envisioned that strap 22 includes a plurality of seams, disposed
variously
thereabout, that join foot contact layer 26 and outer layer 28.
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In an alternative embodiment and with reference to FIG. lA, an exaggerated
partial
cross-sectional view of a strap member 22 and its union to foot sleeve 12 is
shown. The
strap member 22 is disposed between the foot contact layer 32 and outer layer
42 of foot
sleeve 12 such that the union of strap 22 and foot sleeve 12 is generally
uniform. Such
uniformity provides additional comfort to the user of the foot sleeve 12. More
particularly,
foot contact layer 26 and outer layer 28 of strap 22 are joined to interior
portions of foot
contact layer 32 and outer layer 42 of foot sleeve 12. Alternatively, it is
also contemplated
that cushioning layer 30 may or may not be disposed between foot contact layer
32 and
outer layer 42 of foot sleeve 12.
Strap 22 has a longitudinally projecting configuration extending from foot
sleeve 12
and is configured for disposal about portions of foot F adjacent the ankle.
Strap 22 forins
part of a hook and loop type connector. A hook element 33 is mounted to strap
22 at foot
contact layer 26. As strap 22 is wrapped about the portions of foot F adjacent
the ankle,
hook element 33 engages the loop material of outer layer 42 of foot sleeve 12
to facilitate
mounting of foot sleeve 12 with foot F. Alternative to hook and loop type
elements, clips,
adhesive and pins may be employed.
Foot sleeve 12 includes a foot contact layer 32 configured to engage foot F
for
applying pressure thereto. Foot contact layer 32 has sections 35 and is
flexible for
conforming to the shape of foot F. It is envisioned that foot contact layer 32
may be
fabricated from a polyester fabric. It is contemplated that foot contact layer
32 may be
configured for wicking fluids such as, moisture and perspiration from an outer
surface of
foot F. Foot contact layer 32 may be treated chemically to enhance such
wicking effect.
Alternatively, foot contact layer 32 may be monolithically formed with foot
contact layer 26
of strap 22.
An inflatable bladder 34 of foot sleeve 12 includes an upper bladder layer 36
and a
lower bladder layer 38 that are overlaid to form inflatable bladder 34. Upper
bladder layer
36 engages foot contact layer 32 to facilitate application of pressure for
vascular therapy to
foot F. Upper bladder layer 36 and lower bladder layer 38 are fixedly joined
via welding at
seams along their perimeters to define inflatable bladder 34. It is
contemplated that
inflatable bladder 34 may include a plurality of seams, disposed variously
thereabout, that
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join upper bladder layer 36 and lower bladder layer 38. It is further
contemplated that the
seams may be formed by adhesive, heat sealed and the like.
Upper bladder layer 36 and lower bladder layer 38 may be fabricated from a
laminated material, for example, a PVC material. It is contemplated that each
bladder layer
may have a thickness of approximately 6 - 15 mils. It is further contemplated
that the PVC
material may be laminated to a non-woven or woven material and is RF heat
sealable.
Upper bladder layer 36 and lower bladder layer 38 may be fabricated from two
different
thicknesses to provide directional inflation. It is envisioned that the
overall dimensions and
materials described throughout this disclosure are not limiting and that other
dimensions
and materials may be used. It is further envisioned that inflatable bladder 34
may define
one or a plurality of expandable chambers.
Inflatable bladder 34 extends along foot F to apply vascular therapy to the
entire
area of the bottom of foot F, beyond heel H and ball B to a substantial
portion of toes T. It
is contemplated that inflatable bladder 34 may have various geometric
configurations, such
as, circular, elliptical and rectangular. Inflatable bladder 34 includes an
inlet port 40 that
connects to tubing 16 to facilitate fluid communication with pressurized fluid
source 14.
An outer layer 42 of foot sleeve 12 is disposed adjacent to lower bladder
layer 38.
Outer layer 42 may be fabricated from a laminated material including fabric
and a loop
material, for example, a loop/non-woven laminate. Outer layer 42 provides an
attachment
surface for hook elements. Alternatively, outer layer 42 may be monolithically
formed with
outer layer 28 of strap 22.
Outer layer 42 may include die cut holes to provide for a fluid inlet to pass
through,
such as inlet port 40. It is envisioned that outer layer 42 and other portions
of foot sleeve 12
may include vent openings disposed variously thereabout to provide cooling to
the subject
and increase mobility during use.
Foot contact layer 32 and outer layer 42 are overlaid to form foot sleeve 12.
Foot
contact layer 32 and outer layer 42 are fixedly joined at seams adjacent
corresponding
perimeters thereof, to support the components of foot sleeve 12. The
components of foot
sleeve 12 may be bonded via welding, e.g., RF welding, adhesive, industrial
strength double
sided tape and the like. It is envisioned that only a portion of the
perimeters of foot contact
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layer 32 and outer layer 42 are joined. It is envisioned that foot sleeve 12
includes a
plurality of seams, disposed variously thereabout, that join foot contact
layer 32 and outer
layer 42.
The components of foot sleeve 12 may be fabricated from materials suitable for
compression vascular therapy such as, for example, films and fabrics, such as
PVC
(polyvinyl chloride) and PE (polyethylene), depending on the particular
vascular therapy
application and/or preference. Semi-flexible and flexible fabrics, such as
urethanes and
silicones may also be used. Moreover, foot sleeve 12 may be fabricated from
synthetic,
natural, and non-woven materials of varying degrees of softness and
pliability. One skilled
in the art, however, will realize that other materials and fabrication methods
suitable for
assembly and manufacture, in accordance with the present disclosure, also
would be
appropriate.
Foot sleeve 12 is configured to support inflatable bladder 34. Foot sleeve 12
extends
laterally and is configured for disposal about foot F and mounting thereto.
Foot sleeve 12 is
disposed with foot F such that the top portion of toes T are visible for
observation and
inspection. A metatarsal flap 44 of foot sleeve 12 wraps about the side
portions of foot F
and transverses the instep of foot F during vascular therapy. Metatarsal flap
44 forms part
of a hook and loop type connector. A hook element 46 is mounted to foot sleeve
12 at foot
contact layer 32. As metatarsal flap 44 is wrapped about foot F, hook element
46 engages
the loop material of outer layer 42 to facilitate mounting of foot sleeve 12
with foot F. In
turn, this causes inflatable bladder 34 to be disposed about foot F for
vascular therapy. This
configuration of foot sleeve 12 advantageously engages foot F to augment
circulation of
vessels of the limb. It is conteinplated that foot sleeve 12 may have various
geometric
configurations, such as, circular, elliptical, and rectangular. Alternative to
hook and loop
type elements, clips, adhesive, and pins may be employed.
Compression apparatus 10, similar to that described above, is assembled and
packaged for use. In operation, foot sleeve 12 of compression apparatus 10 is
disposed
about foot F and in fluid communication with pressurized fluid source 14, as
discussed.
Controller 20 regulates vascular therapy of compression apparatus 10 to a
subject. Foot
sleeve 12 applies compression to foot F to provide vascular therapy to the
subject and
augment venous return. It is envisioned that compression apparatus 10 may
include
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inflatable sleeves for disposal about various portions of a subject's limb,
such as for
example, thigh, calf, ankle and that a second limb may be treated in alternate
compression
cycles with other sleeve(s).
For example, during a selected compression cycle for controller 20, inflatable
bladder 34 is slowly inflated for 5 seconds with air to a pressure, such as
130 mm Hg. This
configuration provides vascular therapy to foot F and augments venous return.
At the end
of the inflation and hold, foot sleeve 12 is vented and inflatable bladder 34
is deflated.
Other compression cycles and pressures are also contemplated.
In an alternate embodiment, compression apparatus 10 performs venous refill
time
measurement. Venous refill time (VRT) measurement is an air plethysmographic
technique
that determines when the veins of a limb have completely refilled with blood
following a
compression cycle. See, for example, the venous refill time measurement
described in U.S.
Patent No. 6,231,352 to Watson et al., the entire contents of which is hereby
incorporated
by reference herein. The VRT minimizes the amount of time that the blood
remains
stagnant inside the veins. The VRT is substituted for the default rest time
between
compression cycles. It is contemplated that the VRT technique and algorithm
can be used
for both leg sleeve and foot sleeve compression.
The VRT measurement uses an air plethysmographic technique where a low
pressure is applied to inflatable bladder 34. As the veins fill with blood,
the pressure in
inflatable bladder 34 increases until a plateau is reached. The time that it
takes for the
pressure to plateau is the VRT. If two sleeves are connected to controller 20,
then the VRT
is determined separately for each limb being compressed and the greater of the
two
measurements is used as the new vent time of the compression cycle. The VRT
measurement for each sleeve is made as each particular sleeve reaches set
pressure
independently. However, the vent time is not updated until VRT measurements
have been
calculated for both sleeves.
For example, compression apparatus 10 may employ the VRT measurement after the
system initiates vascular therapy. Subsequently, after 30 minutes have
elapsed, a VRT
measurement will be taken on the next full inflation cycle. After foot sleeve
12 inflates,
inflatable bladder 34 is vented down to zero.
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It is contemplated that a selected bladder pressure is monitored and the vent
to the
bladder is closed when the pressure falls to 5-7 mm Hg. If the pressure in the
bladder'is 5-7
mm Hg on a current cycle then a VRT measurement is taken. If the pressure in
the bladder
does not vent down to 5-7 mm Hg then the vent time will remain at its current
value and
another measurement will be made in 30 minutes.
The VRT measurement algorithm determines when the pressure in inflatable
bladder
34 plateaus after compression. The VRT measurement algorithm initiates with a
time
counter started from the end of the inflation cycle, which occurs after
inflatable bladder 34
reaches 5-7 mm Hg (enough pressure to cause the bladder to remain in contact
with the
surface of the foot) and the venting is stopped. The VRT measurement initiates
with the
time counter started from the end of the inflation cycle.
The pressure in inflatable bladder 34 is'then monitored with a 10-second,
moving
sample window. The window moves in 1-second intervals. When the difference
between
the first and last values in the window is less than approximately 0.05 - 0.5
mm Hg, the
curve has reached its plateau. The VRT measurement is considered done, and the
time
interval is determined. The end of the window is considered to be the point at
which the
venous system in the foot has refilled.
The VRT measurement is considered erroneous if at any time during the
measurement, the pressure in inflatable bladder 34 is below 2 mmHg, the
calculation is
discarded, and the old value of VRT is used. This may occur if there is a leak
in the system.
It is contemplated that if the pressure is greater than 20 mmHg at any time
during the VRT
measurement, the old value of the VRT is used. '
Referring to FIG. 4, an alternate embodiment of compression apparatus 10 is
shown.
Compression apparatus 10 includes a foot sleeve 212, similar to foot sleeve 12
described
above with regard to FIGS. 1, lA and 2, configured for disposal about foot F.
A pair of
straps 222, similar to strap 22 described above with regard to FIGS. 1, lA and
2, extend
from foot sleeve 212. Straps 222 are configured for disposal about foot F
adjacent to the
ankle. One or a plurality of straps 222 may be employed.
Straps 222 have a longitudinally projecting configuration extending from foot
sleeve
212 and are configured for disposal about portions of foot F adjacent the
ankle. As
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discussed herein, it is contemplated that straps 222 may be separately or
monolithically
formed with foot sleeve 212. Straps 222 form part of hook and loop type
connectors. Hook
element 232 and loop element 232a are mounted to straps 222. As each of straps
222 are
wrapped about the portions of foot F adjacent the ankle, hook element 232
engages loop
material 232a to facilitate mounting of foot sleeve 212 with foot F. It is
contemplated that
hook elements 232, 232a may engage loop material disposed with an outer
surface of foot
sleeve 212 to facilitate mounting of foot sleeve 212 with foot F.
An inflatable bladder 234, similar to bladder 34 described above with regard
to
FIGS. 1 and 2, extends longitudinally along foot F to apply vascular therapy
to the entire
area of the bottom of foot F, beyond heel H and ball B to a substantial
portion of toes T.
Inflatable bladder 234 includes an inlet port 240 that connects to tubing 16
to facilitate fluid
communication with pressurize,d fluid source 14.
Foot sleeve 212 is configured to support inflatable bladder 234. Foot sleeve
212
extends laterally and is configured for disposal about foot F and mounting
thereto. Foot
sleeve 212 is disposed with foot F such that the top portion of toes T are
visible for
observation and inspection. A pair of metatarsal flaps 244 extend laterally
from foot sleeve
212 for wrapping about the side portions of foot F and transversing the instep
of foot F
during vascular therapy. Metatarsal flaps 244 form the hook and loop type
connectors.
Hook element 246 and loop element 246a are mounted to foot sleeve 212. As
metatarsal
flaps 244 are wrapped about foot F, hook element 246 engages to loop element
246a to
engage the foot sleeve 212 to facilitate mounting of foot sleeve 212 with foot
F. In turn,
this causes inflatable bladder 234 to be disposed about foot F for vascular
therapy. This
configuration of foot sleeve 212 advantageously engages foot F to augment
circulation of
vessels of the limb. Foot sleeve 212 includes vent openings 250 disposed to
provide
cooling to the subject and increase mobility during use.
Referring to FIG. 5, another alternate embodiment of compression apparatus 10
is
shown. Compression apparatus 10 includes a foot sleeve 312, similar to those
described
above, configured for disposal about foot F. A strap 322, similar to those
described above,
extends from foot sleeve 312. An inflatable bladder 334, similar to those
described above,
extends longitudinally along foot F to apply vascular therapy to the entire
area of the bottom
of foot F, beyond heel H and ball B to a substantial portion of toes T.
Inflatable bladder 334
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includes side portions 336 that extend laterally therefrom to engage side
portions of foot F
during application of foot sleeve 312 with foot F.
Foot sleeve 312 is configured to support inflatable bladder 334. Foot sleeve
312
extends laterally and is configured for disposal about foot F and mounting
thereto. Foot
sleeve 312 is disposed with foot F such that the top portion of toes T are
visible for
observation and inspection. A pair of metatarsal flaps 344 extend laterally
from one side of
foot sleeve 312 for wrapping about the side portions of foot F and
transversing the instep of
foot F during vascular therapy. Metatarsal flaps 344 form part of hook and
loop type
connectors. Hook elements 346, 346a are mounted to foot sleeve 312. As
metatarsal flaps
344 are wrapped about foot F, hook elements 346, 346a engage the loop material
of foot
sleeve 312 to facilitate mounting of foot sleeve 312 with foot F. In turn,
this causes
inflatable bladder 334 to be disposed about foot F, including side portions
336 engaging the
side portions of foot F, for vascular therapy. This configuration of foot
sleeve 312
advantageously engages foot F to augment circulation of vessels of the limb.
Referring to FIG. 6, another alternate einbodiment of compression apparatus.
10 is
shown. Compression apparatus 10 includes a foot sleeve 412, similar to those
described
above, configured for disposal about foot F. A strap 422, similar to those
described above,
extends from foot sleeve 412. An inflatable bladder 434, similar to those
described above,
extends longitudinally along foot F to apply vascular therapy to the bottom of
foot F,
beyond heel H and ball B to a substantial portion of toes T.
Foot sleeve 412 has wings 444 (similar to metatarsal flaps described above)
and is
configured to support inflatable bladder 434. Foot sleeve 412 extends
laterally, via wings
444, and is configured for disposal about foot F and mounting thereto. Foot
sleeve 412 is
disposed with foot F such that the top portion of toes T are visible for
observation and
inspection. Wings 444 wrap about the side portions of foot F and transverse
the instep of
foot F during vascular therapy. Wings 444 form part of hook and loop type
connectors.
Hook element 446 and loop element 446a are mounted to wings 444. As wings 444
are
wrapped about foot F, hook element 446 engages with loop element 446a to
facilitate
mounting of foot sleeve 412 with foot F. In turn, this causes inflatable
bladder 434 to be
disposed about foot F for vascular therapy. This configuration of foot sleeve
412
advantageously engages foot F to augment circulation of vessels of the limb.
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Referring to FIG. 7, another alternate embodiment of coinpression apparatus 10
is
shown. Compression apparatus 10 includes a foot sleeve 512, similar to those
described
above, configured for disposal about foot F. A strap 522, similar to those
described above,
extends from foot sleeve 512. An inflatable bladder 534, similar to those
described above,
extends longitudinally along foot F to apply vascular therapy to the bottom of
foot F,
beyond heel H and ball B to a substantial portion of toes T. Inflatable
bladder 534 includes
longitudinal portions 536 that extend longitudinally therefrom to engage
desired portions of
the bottom of foot F during application of foot sleeve 512 with foot F. Foot
sleeve 512 is
configured to support inflatable bladder 534. This configuration of foot
sleeve 512
advantageously engages foot F to augment circulation of vessels of the limb.
It will be understood that various modifications may be made to the
embodiments
disclosed herein. Therefore, the above description should not be construed as
limiting, but
merely as exemplification of the various embodiments. Those skilled in the art
will
envision other modifications within the scope and spirit of the claims
appended hereto.
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