Note: Descriptions are shown in the official language in which they were submitted.
CA 02702703 2010-05-04
TITLE: Internal Structural Configurations of Bladders Used in Patient
Support Systems
PRIORITY CLAIM
[0001] This application claims the benefit of previously filed U.S.
Provisional
Patent Application entitled "Internal Structural Configurations of Bladders
Used in
Patient Support Systems," assigned USSN 61/176,555, filed May 8, 2009, and
which is incorporated herein by reference for all purposes.
FIELD OF THE INVENTION
[0002] This subject matter generally relates to internal structural
configurations for bladders used in support surfaces for preventing, reducing,
and/or treating decubitus ulcers, also known as pressure sores or bedsores.
BACKGROUND OF INVENTION
[0003] The present subject matter generally relates to bladders and air
cylinders used in patient support surfaces and more particularly to
combinations of
foam and air or fluid technologies which are selected so as to lend themselves
to
certain common modular assembly features, in the context of improved
performance and/or costs.
[0004] Particularly in the field of healthcare, there has been a long felt and
profound need to provide pressure relief for immobile or otherwise confined
patients. For a tremendous variety of reasons, many patients must withstand
long
periods of bed rest or other forms of confinement, such as use of a wheelchair
or
other accommodating but restrictive support arrangement. In those instances,
there is a tremendous risk that exposure to excess pressure, or longer term
exposure to relatively lower pressure levels, can result in painful and even
1
CA 02702703 2010-05-04
dangerous sores and other conditions in addition to decreased oxygen uptake,
loss of bone mass, loss of skin integrity, loss of appetite, and decreased
cardiovascular functioning.
[0005] Literally an entire segment of the healthcare industry is directed to
the study and treatment of various tissue traumas, such as decubitus ulcers.
Tissue damage can be monitored and rated, with progressively higher ratings
warranting more involved treatment approaches. For example, the Braden Scale
is an assessment tool for determining a patient's risk level for incurring
skin
breakdown. Consequently, the healthcare industry perceives and evaluates
treatment options on the basis of their ability to address conditions at such
different
stages or ratings.
[0006] Healthcare costs, generally, as well as patient well being may be
greatly affected by the degree of pressure relief for patients confined to
beds for
significant periods of time. Pressure sores (e.g. decubitus ulcers),
potentially
leading to infections and other worsened conditions or complications can occur
from prolonged pressure exposure, such as experienced by those confined to
beds, whether in a hospital, nursing home, or private residence. Considerable
efforts have been made to provide mattress systems or patient support surfaces
which effectively redistribute and equalize pressure forces at the
interactions
between the patient and the support surface. Generally speaking, the more
sophisticated techniques for achieving such pressure reductions are relatively
more involved and therefore more expensive to manufacture and/or use. Certain
generally effective techniques involve the use of elongated air tubes or
cylinders
variously combined with foam pieces. Examples of embodiments having a
plurality
(such as four) of generally longitudinal elongated air tubes are set forth in
commonly owned U.S. Pat. Nos. 5,070,560 and 5,412,821. Such patents include
the use of relatively stiffened lateral slats to help convey and redistribute
forces
laterally from one air tube to another. Such redistribution takes place over
relatively limited areas of contact between the respective elements. While
such
approach is generally effective, one aspect of the present subject matter
seeks to
improve on the redistribution and equalization of pressure forces in the
context of
using such elongated air tubes and to otherwise improve the function thereof.
2
CA 02702703 2010-05-04
[0007] Typically, various support systems have made use of resilient
support bodies, such as strips or blocks of foam, or some other support
bladder
containing a specific fluid. Mattress technologies, in general, have often
made use
of other resilient support media, such as springs, slats, or various support
fillers,
such as ticking. Different gases, often such as air, or various liquids have
been
used, including relatively viscous liquids, such as gels. In some instances,
combinations of the above various technologies have been used.
[0008] One aspect of support systems, especially concerning those for use
with recumbent patients, is that they are faced with distinctly different
loading
requirements along the longitudinal axis thereof. In other words, certain body
areas of a patient will be heavier than others, thereby generally requiring
greater
support in such longitudinal areas if pressure relief is to be optimized.
[0009] As a result, various support pads have sought to provide
sectionalized support. One such resilient foam pad making use of a uniform
patterned surface, though with differential resilient support responsive to
different
loads, is U.S. Pat. No. 5,007,124 entitled "Support Pad with Uniform Patterned
Surface."
[0010] As foam surface patterns become more sophisticated, there is a
corresponding increase in the difficulty of producing such articles. One
example of
a three section foam mattress is U.S. Pat. No. Des. D336,400, entitled "Foam
Mattress Pad." Another example of a still more complicated foam mattress
surface, typically requiring a computer controlled cutting machine for
production, is
U.S. Pat. No. 4,862,538, entitled "Multi-Section Mattress Overlay for
Systemized
Pressure Dispersion."
[0011] Still further examples of various resilient foam support pads and the
like, and certain aspects of manufacture thereof, are shown by U.S. Pat. Nos.
4,603,445; 4,700,447; Des. D307,688; Des. D307,689; Des. D307,690; 5,025,519;
Des. D322,907; and 5,252,278. Generally speaking, as support surface designs
become more entailed, they become more difficult and more expensive to
produce.
At the same time, regardless of the manufacturing cost, they provide a
generally
static or preset response to loading changes, i.e., changes in the weight of
the
patient being supported in a specific region of the pad. Such variations may
occur
3
CA 02702703 2010-05-04
due to the variations among patients, or simply to the movement of an
individual
patient.
[0012] One example of a pressure relief support system utilizing fluid filled
chambers is shown by U.S. Pat. No. 5,070,560, entitled "Pressure Relief
Support
System for a Mattress." In such patent, sealed longitudinal air cylinders are
provided in the shape of a mattress, otherwise having various transverse slats
and/or foam strips or members. Such a support system offers air dispersion
pressure treatment in a static design which avoids the relative extremely high
cost
and other negative factors often associated with active air bed systems.
[0013] Highest rated pressure relief support systems typically involve beds
having a plurality of fluid filled chambers, the internal pressures of which
are
maintained at a constant pressure by a relatively higher technology dynamic
system approach. Specifically, each fluid filled support element may be
associated
with its own control valve, alternately permitting ingress and egress of
fluid.
Various pressure sensitive detection devices typically may be utilized in a
feedback control system for determining that an excess pressure condition (or
a
subpressure condition) exists. Thereafter, the control technology is operative
for
bleeding off excess pressure by selected valving operation (such as dumping
excess fluid into a reservoir arrangement) or for actively pumping in
additionally
needed fluid.
[0014] As such, the above higher technology systems require various
motors, pumps, valving systems, sensory feedback arrangements, and control
systems for all the foregoing. Due to their complicated construction and
design,
such beds are typically more expensive with respect to initial purchase or
rental
cost. They can also be complicated and expensive to maintain due to the
prospect
of failure of numerous moving mechanical parts, and due to the extensive
training
which an operator or maintenance person would be required to undergo.
[0015] Also, there is the prospect of highly undesired heat transfer to a
patient, due to operation to the above-referenced motors, pumps and other
systems. Still further, the construction and design of such overall systems
often
require specialized bed frames not otherwise usable with typical mattresses.
[0016] Typically, air or fluid flows among the bladders disposed in a patient
support surface in response to the weight of the body to equalize pressure
4
CA 02702703 2010-05-04
throughout the system, provide a constant, uniform distribution of safe
pressures
beneath the patient, and prevent bottoming out of the support surface. The
bladders are air or liquid filled, as discussed above, or may be a bladder
with a
foam insert such as those described by Giori et al. in U.S. Patent No.
6,922,863,
Michiels in U.S. Patent No. 4,407,031, Bondie et al. in U.S. Patent No.
6,588,038,
Stinson et al. U.S. Patent No. 5,388,292, Stolpman et al. US RE38,135.
[00171 The existing bladders used in patient support platforms, either air,
liquid or air/liquid/foam filled, while providing a surface for a patient,
have various
failings. Air or fluid filled bladders achieve, through volume modulation, a
very soft
feel for the user. However, air or liquid filled bladders are subject to
deflation if
pierced while in use as well as "hammocking" or "bottoming out" wherein the
patient comes to rest on the substrate beneath the bladder due to insufficient
support. The problem with pressurized air supported surfaces is that if air
were
allowed to escape the pressurized chamber, the support surface would collapse
and cause a hammock effect.
100181 Bladders that use foam inserts within an air filled bladder fail to
provide the measure of comfort associated with an air or liquid filled
mattress.
Foam adjusts to the patient's body's pressure points locally by the density of
the
foam increasing as the foam is compressed by pressure from the patient's body.
Further, too soft of a foam can mimic the hammock or bottoming out experienced
with air or liquid filled bladders. Moreover, the foam inserts impede the flow
of air
through the bladder, thus preventing or significantly slowing the ability of
the
support surface to adjust to the patient. Also, an undesirable characteristic
of
open-cell flexible polyurethane foam is that it can potentially solidify in a
full
vacuum-state, a so-called 'compression set' (CS). If too much air is removed
from
the cellular structure of foam, it will harden in its densest state and
subsequently
no longer be able to self-inflate and regain its loft, even partially. CS
becomes
critical when foam has been compressed for an extended period of time.
100191 There exists a need for a simplified design for bladders or air
cylinders used in patient support systems which give the clinician the needed
options in addressing integrity of the skin and deep tissues. A need exists to
provide a bladder which is simple to construct as well as providing a method
of
equalizing pressure over the surface of the body by means of interconnected
air-
5
CA 02702703 2010-05-04
filled tubes that shift air from tubes under more pressure to tubes under less
pressure. This allows greater immersion of the body into the mattress, which
decreases pressures under any single point, and distributes pressures over as
great an area as possible. There also exists a need to combat the
aforementioned
failings associated with air filled, liquid filled and air/liquid/foam filled
bladders by
providing a bladder that combines the support and comfort of an air or liquid
mattress with the structural support provided by a foam insert without
diminishing
the ability of the patient support surface to rapidly adjust to pressure
changes.
[0020] The disclosure of all U.S. patents noted in this application, above or
hereinafter listed, are fully incorporated herein by reference to the extent
not
inconsistent herewith.
SUMMARY OF THE INVENTION
[0021] The present subject matter recognizes and addresses various of the
foregoing problems, and others, concerning the bladders or air cylinders
present in
patient support surfaces. Thus, broadly speaking, a principal object of this
subject
matter is improved patient support surfaces via improved bladders. More
particularly, a main concern is improved patient support surfaces of the type
involving bladders or air cylinders using combinations of foam and air or
liquid
technology. Such patient support surfaces are provided for receiving a patient
thereon, and have at least one adjustable fluid support bladder with fluid
therein.
Multiple fluid support bladders may be used in additional embodiments and
various
forms of foams and fluids may be practiced throughout all such embodiments.
[0022] The present subject matter is directed to a bladder comprising an
outer surface, an inner surface, a length, a height, a width, and first and
second
ends. The bladder has an internal volume. There is a support structure
disposed
within the bladder wherein the support structure comprises a length, a width,
a
height, an inner region, and an outer region wherein the outer region of the
support
structure comprises support projections which define openings in the outer
region
of the support structure. The support projections have an engaging end which
contacts the inner surface of the bladder and exerts force upon the inner
surface of
the bladder to maintain the internal volume of the bladder in a no-load state.
A no-
6
CA 02702703 2010-05-04
load state is the condition of the patient support surface when a patient is
not
present on the surface.
[0023] In one exemplary embodiment, the support structure comprises less
than 90% of the internal volume of the bladder. In other embodiments, it may
comprise less than 80% whereas in further embodiments it may comprise less
than 70% or even less than 60%. In one preferred embodiment, it may comprise
about 80%. More broadly, it is to be understood by those of ordinary skill in
the art
that the present subject matter is intended as having a foam-to-air ratio
relatively
as low as possible while still being able to have the foam component to
restore the
unloaded volume of the tube. So, for various embodiments depending on their
specifics, it is understood that such ratio will vary.
[0024] An exemplary support structure in accordance with the present
subject matter can be a single piece or multi-piece construct with support
projections extending outward from the inner region. The support structure may
extend the full length of the bladder or extend only partially along the
length of the
bladder. In another embodiment, there is more than one support structure
enclosed within the bladder. In still another present exemplary embodiment,
the
inner region of the support structure defines a cavity in the interior of the
inner
region. In still another exemplary embodiment, the inner region of the support
structure defines more than one cavity in the inner region of the support
structure.
The cavities can extend partially or entirely through the length of the
support
structure.
[0025] With respect to the support projections, these may extend radially
outward from the inner region. In one embodiment, there are at least three
support
projections extending from the inner region. In other embodiments, more than
three, such as four, fix or six or more support projections extend from the
inner
region. In accordance with the present subject matter, the spacing of the
support
projections with respect to one another can vary. They may be spaced evenly
apart with respect to one another or they may be randomly spaced with respect
to
one another.
[0026] In yet another embodiment, the bladder has support projections
comprised of a base which is integral with the inner region of the support
structure,
a body which has a length and extends away from the base, and the engaging end
7
CA 02702703 2010-05-04
has a terminal area which engages the inner surface of the bladder. In further
embodiments, the support projection may have a uniform width along
substantially
all of its length. In other embodiments, the support projection may taper
along its
length toward the terminal point.
[0027] In another embodiment, the terminal area on a support projection can
be a point, a convex rounded surface, a concave rounded surface, a flat
surface,
or combinations thereof. Moreover, different support projections may have
different terminal ends. For example, in an embodiment with six support
structures, three could have terminal areas that are points, one a concave
rounded
surface and two flat surfaces in order to aid with defining the structure of
the
bladder.
[0028] In yet another embodiment, the bladder is in a patient support
surface and has an exterior, an interior, a length, a height, a width and
first and
second ends. The bladder is flexible and can expand and contract. There is a
support enclosed within the interior of the bladder. The support may comprise
an
inner core and outer projections extending radially from the inner core. The
outer
projections may define a space between each outer projection and the next
adjacent outer projection. The outer projections may each have engaging ends
which engage the interior of the bladder and keep the bladder expanded by
exerting an outward force when the bladder is in a no load state.
[0029] In yet another embodiment, there is a modular patient support
assembly comprising plural patient support air cylinders. The air cylinders
comprise an outer surface, an inner surface, a length, a height, a width,
first and
second ends. The air cylinders have an internal volume. There is a support
structure disposed within the air cylinders wherein the support structure
comprises
a length, a width, a height, an inner region, an outer region wherein the
outer
region comprises support projections which define openings in the outer region
of
the support structure. The support projections have an engaging end which
contacts the inner surface of the air cylinders and exerts force upon the
inner
surface of the air cylinders and maintain the internal volume of the air
cylinders in a
no-load state. There may be a resilient foam perimeter surrounding said air
cylinders and supplemental inner bolsters provided within an inside perimeter
defined by said resilient foam perimeter. There is also an upper foam topper
8
CA 02702703 2010-05-04
covering said air cylinders and including underside multiple curved
projections
interoperative with said air cylinders for positional stabilizing. A
surrounding cover
may also be utilized.
[0030] Another present general object is to provide a fully self-adjusting
pressure relief system which optimizes pressure dispersion, while still using
a
relatively inexpensive and simple designs so as to obviate the need for
motors,
control systems, or specialized bed frames or training associated with its use
and,
maintenance.
[0031] Yet another object is to provide a pressure relief support system
which is self-adjusting to allow for more even body weight distribution,
thereby
improving the reduction of pressure on the tissue and skin of a user. At the
same
time, it is an object to provide a self-adjusting technology which may be
customized, as desired, for different patient uses, and for different
alternate uses.
[0032] More specifically, it is a present object to provide a self-adjusting
pressure relief technology which is usable with virtually any type of fluid
(gas,
liquid, relatively viscous liquids), and which is usable in a variety of
settings.
Specifically, it is intended to provide such self-adjusting technology usable
in both
medical and commercial fields, including both mattress-related technologies
and
seating technologies, as well as others. In the area of medical uses, it is
intended
to provide a system and improved technology which is usable in space critical
circumstances, such as involving X-ray, operating room, or NMR technology
uses.
It is intended for the present technology to be equally applicable to critical
care
situations, emergency room gurneys, ambulance stretchers, and medical seating
systems of all types, such as wheelchairs or geriatric chairs.
[0033) It is another present object to provide a self-adjusting technology
with
the advantages of active (i.e., dynamic) fluid-based systems, but with such
simplicity that the technology may be extended to every day consumer products,
such as ergonomic chairs and car seats, as well as consumer mattress
replacement systems, mattresses and mattress overlays (as would also be
applicable in the medical field).
[0034] It is a still further object of the present subject matter to provide a
technology capable of being customized to provide specialized support
surfaces,
9
CA 02702703 2010-05-04
such as for pregnant women, or for amputees or other persons requiring
nonconventional support needs for either sitting or sleeping or bed rest.
[0035] Still further, it is a present object to provide improved technology
applicable in a broad sense virtually to any circumstance of bodies in rest.
For
example, such technology may be incorporated into specialized pillows, such as
in
the case of head injuries involving swelling or other weight changes.
Likewise, the
present technology would be equally applicable to packaging arrangements (such
as for fragile equipment) where it is desired to minimize or limit pressures
associated with transfer shock or the like.
[0036] One present exemplary embodiment relates to a patient support
system for the prevention and treatment of decubitus ulcers. Such an exemplary
patient support system may preferably comprise a foam shell defining an
internal
cavity; a plurality of air cells housed in such internal cavity; and a cover
encasing
such foam shell. With such exemplary arrangement, preferably such plurality of
air
cells respectively each comprises a bladder and an internal support structure
comprised of resilient material and only partly in contact with such bladder.
[0037] Another present exemplary embodiment may relate to a patient
support assembly, comprising plural patient support cylinders; a resilient
foam
perimeter surrounding such air cylinders; an upper foam topper covering such
air
cylinders; and a surrounding cover. Preferably, in such exemplary arrangement,
such cylinders respectively include fluid and foam inserts having support
projections supporting associated of such cylinders; and such cylinders are
positioned one of generally longitudinally and generally laterally within such
resilient foam perimeter.
[0038] In yet another present exemplary embodiment of the present subject
matter, a support system may preferably include a plurality of fluid receiving
cells,
with each of such cells including at least one foam insert having internal
support
structure only partly in contact with an associated cell.
[0039] Additional objects and advantages of the present subject matter are
set forth in or will be apparent to those of ordinary skill in the art from
the detailed
description which follows. Also, it should be further appreciated that
modifications
and variations to the specifically illustrated and discussed features, steps
or
materials hereof may be practiced in various embodiments and uses of this
subject
CA 02702703 2010-05-04
matter without departing from the spirit and scope thereof, by virtue of
present
reference thereto. Such variations may include, but are not limited to,
substitution
of equivalent means and features, materials or steps for those shown or
discussed, and the functional or positional reversal of various parts,
features,
steps, or the like.
[0040] Still further, it is to be understood that different embodiments, as
well
as different presently preferred embodiments, of this subject matter may
include
various combinations or configurations of presently disclosed features, steps,
or
elements, or their equivalents (including combinations of features or steps or
configurations thereof not expressly shown in the Figures or stated in the
detailed
description). Also, it is to be understood that various features from one
embodiment; as illustrated, discussed or suggested, may be combined with or
substituted for features of other disclosed or suggested embodiments, within
the
spirit and scope of the present subject matter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0041] A full and enabling disclosure of the present subject matter, including
the best mode thereof, directed to one of ordinary skill in the art, is set
forth in the
specification, which makes reference to the appended Figures, in which:
[0042] FIGURE 1 is an exploded view of a prior art device wherein
representative bladders are shown in relation to other elements, collectively
comprising a patient support surface;
[0043] FIGURE 2 is a perspective view of a prior art device wherein
representative bladders are shown in relation to other elements, collectively
comprising a patient support surface;
[0044] FIGURE 3A is a top plan view of a prior art device wherein
representative bladders are disposed parallel to the user's body in a patient
support surface;
[0045] FIGURE 3B is a top plan view of a prior art device wherein
representative bladders are disposed perpendicular to the user's body in a
patient
support surface;
11
CA 02702703 2010-05-04
[0046] FIGURE 4 is a perspective view of one exemplary embodiment of the
present subject matter, showing exemplary support structure and an enclosing
bladder;
[0047] FIGURE 5A is a perspective view of one embodiment of the present
subject matter illustrating an exemplary support structure without an
enclosing
bladder;
[0048] FIGURE 5B is a perspective view of another embodiment of the
present subject matter, showing an alternative exemplary support structure
without
an enclosing bladder, where such exemplary support structure has a four point
star
cross-sectional configuration;
[0049] FIGURE 5C is a perspective view of yet another embodiment of the
present subject matter showing an alternative exemplary support structure
without
a bladder, where such exemplary support structure has a cog or gear-shaped
cross-sectional configuration;
[0050] FIGURE 5D is a perspective view of a further embodiment of the
present subject matter showing an alternative exemplary support structure
without
a bladder, where such exemplary support structure has a cross-shaped cross-
sectional configuration;
[0051] FIGURE 6 is an end elevation view of one end of the exemplary
support structure and bladder as shown in present FIGURE 4, and illustrating
engagement of such exemplary support structure with the interior of such
exemplary bladder;
[0052] FIGURE 7A is an end elevation view of one end of an alternative
embodiment of the support structure and bladder as generally shown in present
FIGURE 4, wherein such exemplary support structure has support projections
with
convex shaped engaging ends, based on truncated projections; and
[0053] FIGURE 7B is an end elevation view of one end of a further
alternative embodiment of the support structure and bladder generally as shown
in
present FIGURE 4, wherein such exemplary support structure has a five pointed
star shaped support structure with pointed engaging ends.
[0054] Repeat use of reference characters throughout the present
specification and appended drawings is intended to represent same or analogous
features, elements, or steps of the present subject matter.
12
CA 02702703 2010-05-04
[0055] It is to be understood that the present language is by way of example
and description only and is not intended to limit the broader scope of the
present
subject matter as otherwise disclosed herewith, including features as
referenced in
the Figures.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0056] Reference will now be made in detail to presently preferred
embodiments of the present subject matter, examples of which are discussed in
conjunction with the accompanying drawings. Such examples are provided by way
of an explanation of the present subject matter, not limitation thereof. In
fact, it will
be apparent to those skilled in the art that various modifications and
variations can
be made in the present subject matter, without departing from the spirit and
scope
thereof. For instance, features illustrated or described as part of one
embodiment
can be used on or in another embodiment to yield a still further embodiment.
Still
further, variations in selection of materials and/or characteristics may be
practiced,
to satisfy particular desired user criteria. Thus, it is intended that the
present
subject matter cover such modifications and variations as come within the
scope of
the present features and their equivalents.
[0057] Particularized definitions used herewith include:
ILD - Indentation Load Deflection or IFD - Indentation Force Deflection -
measure of the stiffness of open-cell foam which measures conformability or
ability to immerse the patient to distribute weight as well as measures the
compressibility or the ability to support the patient and prevent bottoming
out. Measured as the number of pounds needed to indent a 4" x 12" x 12"
sample of the foam with a 50 square inch circular plate a certain distance.
25% ILD/IFD - indents the foam 25% of the way through the sample, or 1".
65% ILD/IFD - indents the foam 65% of the way through the sample, or 2.5".
No-Load State - the condition of the patient support surface when a patient
is not present on the surface.
[0058] While in accordance with the present subject matter no particular
measurements are contemplated as necessary or required with respect to the
outward forced applied by the support projections on the inner surface of the
13
CA 02702703 2010-05-04
bladder, the present subject matter does consider the "preload" on the star
(or
other design) tips based on the amount of interference between the tube
diameter
and the star "diameter". For example, the present subject matter may encompass
a range of designs, from the radius of the star being 10% larger than the
radius of
the tube to the radius of the star being 20% smaller than the radius of the
tube, or
even designs outside of such range. In general, those of ordinary skill in the
art
will appreciate that one of the trade-offs to be considered in any given
embodiment
is the level of functionality desired versus the desired cost of manufacturing
for a
particular foam-in-tube design, all of which variations are intended as being
encompassed by the present disclosure.
[0059] Applicant hereby incorporates by reference, in their entirety, U.S.
Patent Nos. 6,782,574 and 6,223,369, to the extent not inconsistent herewith.
[0060] FIGURE 1 is an exploded generally top and mostly end perspective
view of a prior art patient support surface wherein a plurality of generally
longitudinally-place bladders 100 are shown in relation to other elements
comprising a patient support surface. U.S. Patent Nos. 6,223,369 and 6,782,574
disclose a patient support surface into which presently disclosed bladders
could be
incorporated and are hereby incorporated fully by reference. Patient support
surface 34 includes a foam topper 24 which may be integrally included within
the
patient support surface. Particularly, the upper support surface of such foam
topper may include a variety of constructions designed and intended to
facilitate
pressure relief. Pressure relief, for example, may be provided by a number of
lateral cuts or channels generally 26 formed in such surface as illustrated in
solid
line. Another aspect of the patient support surface is a pair of inner
bolsters 68
and 70, which run longitudinally along the lengthwise axis of patient support
surface 34. As illustrated, each inner bolster 68 and 70 has a respectively
inwardly
facing concave surface 72 and 74 which interacts with part of the curvature of
respective air bladders 200. Still further, each concave face 72 and 74 is
provided
with at least one respective curved slot 76 and 78, respectively, therein, for
purposes as further discussed below.
[0061] Patient support surface 34 also includes perimeter bolster
components 16 and 18. These may be of relatively more dense material for
relatively greater support than side or inner bolsters 68 and 70, which in
turn may
14
CA 02702703 2010-05-04
be of relatively greater density or firmer support than foam topper 24. As
shown, a
plurality of depending elements 82, 84, and 86 constitute projections which
approximate inverted contoured triangles. Otherwise formed in the underside
surface 80 of foam topper 24 are a plurality of downwardly facing arches
generally
88, 90, 92, and 94. As will be understood by those of ordinary skill in the
art, such
respective arches run along the longitudinal length of foam topper 24 formed
in the
underneath side 80 thereof. Likewise, the underside arches interact and
interface
with the generally top sides of the respective bladders 100, such that the
depending elements 82, 84, and 86 work into the areas between the respective
bladders 100. The resulting combination cradles and surrounds the bladders,
providing an interlocked, integrated design having flexible, progressive
support
while maximizing structural integrity. Such integrated structural integrity
includes
the beneficial tube capturing effects of the side or inner bolsters 68 and 70,
as well
as the beneficial effects of perimeter bolster 14 as shown by present FIGURE
2.
[0062] FIGURE 2 is a generally top and partial side perspective view, in
partial cutaway, of a prior art patient support surface.
[0063] FIGURES 3A and 3B are respective top plan views of prior art
devices, representing bladders 100 can be disposed parallel to the user's body
in a
patient support surface 34, or with bladders generally 102 disposed
perpendicularly to the user's body.
[0064] It is to be understood that any of the various exemplary support
structure and enclosing bladders disclosed herewith per present subject matter
may be variously incorporated in place of bladders 100 and/or 102 of the
foregoing
exemplary patient support surfaces. Likewise, present exemplary support
structure and enclosing bladders may be utilized in conjunction with other
forms of
patient support surfaces, or in other entire arrangements.
[0065] FIGURE 4 is a perspective view of one embodiment of the present
subject matter showing an exemplary support structure 216 and a representative
enclosing bladder 200. It is to be understood that the various exemplary
support
structures of the present subject matter may be utilized in conjunction with
such
enclosing bladders, as desired for different present embodiments, all of which
in
turn may be used in the representative patient support surfaces described
herein,
or in other combinations.
CA 02702703 2010-05-04
[00661 The exemplary support structure generally 216 of present FIGURE 4
can be formed from any suitable composition including foam, plastic, meitblown
or
spunblown materials or other suitable structural materials known to those
skilled in
the art. One presently preferred example may be polyurethane foam or even a
combination of different density/ILD polyurethane foams that are laminated
together. For example, one may use HR11 Ca Dark Green polyurethane made by
NCFI, 2#/ft3, 13 ILD Ca117. Other non-limiting examples may include the
following, selected also in conjunction with the turn angle when needed and
the
desired level of comfort. Several of the more important properties are stated
below
in density and ILD, for three different examples regarding three different
kinds of
foam for the Star Chamber air cylinders:
Exemplary Foam Density ILD
HR11 Ca Dark 2.0 pounds per cubic foot 13 pounds
Green
PRS35 Ca Tan 2.25 pounds per cubic 35 pounds
foot
UC11 1.5 pounds per cubic foot 14 pounds
[00671 Examples of particularly suitable foams include polyethylene,
polyurethane, polyester, straight chain or cross-linked varieties of each as
well as
combinations of polyethylene, polyurethane, and polyester foams. Preferably
the
foam will have a density range of about 1.5 to about 2.5 Ibs/ft3 and an
IFD/ILD
range of about 12 to about 15. The foam can be either an open cell or a closed
cell type foam. With an open cell foam, air flows through the foam cells as
the air
travels from one chamber to another. With a closed cell foam, air on the
surface of
the foam is allowed to flow between the foam and bladder 200. Upon impact or
load, the air contained within the closed cells is also compressed.
[00681 The exemplary support structure 216 comprises a length 218, a width
220, a height 222 and has a volume and can assume any shape known to those
skilled in the art. Particularly preferable shapes include those comprising
projections extending from a central core or central region such as a star or
gear
shape. Support structure 216 also comprises support structure first face 224
and
support structure second face 226. The foam can have either an open or a
closed
16
CA 02702703 2010-05-04
cell structure. In one preferred embodiment, an open cell structure is used.
As
shown by respective FIGURES 5A-5D, exemplary alternative shapes respectively
217, 219, 221, and 223 of the support structure 216 are envisioned.
[0069] As shown by FIGURE 6, the exemplary support structure 216 also
comprises an inner region generally 228 with support projections 230 extending
outwardly from inner region 228. Such support projections 230 preferably
define
openings generally 232. Openings 232 are unbounded by the support structure
216 in at least one direction. For purposes of example only, when the openings
232 are in the shape of a triangle, the base of the triangle (which would face
toward the inner surface of the bladder 200) is open and not enclosed by the
support structure 216, while the sides of the triangle are otherwise enclosed
by the
support structure 216.
[0070] The support projections 230 and openings 232 comprise outer region
generally 234, which is the region of the bladder comprised of the support
projections 230 and the openings 232 they define.
[0071] Openings 232 can extend the length of the support structure 216.
Each opening 232 is defined by two support projections 230. In an alternative
embodiment, openings 232 may only extend partially through a present support
structure, such as structure 216 (or any other present embodiments). In a
further
embodiment, openings 232 may originate at both support structure first end 224
and support structure second end 226, and may be offset with respect to one
another as the openings 232 extend the length of the support structure 216.
[0072] Support projections 230 have an engaging end 236 located away
from the inner region 228 which comprises the portion of the support structure
216
not including the support projections 230 and the openings 232 they define.
[0073] In a further embodiment, inner region 228 may define a cavity 238
which can extend throughout the length of support structure 216.
Alternatively,
cavity 238 may only extend partially along the length of support structure
216.
Cavity 238 may be any shape known to those of skill in the art but is
representatively illustrated in FIGURE 6 as a circle for illustrative purposes
only. In
a further embodiment, cavity 238 may be present on support structure first
face
224 and support structure second face 226, present on one or the other or
present
on neither yet contained within support structure 216 in a "hollow"
configuration.
17
CA 02702703 2010-05-04
[0074] Support projections 230 also have a support projection base 240 as
illustrated by the dashed line PB on FIGURE 6 and a support structure body
length
241 illustrated by dashed line BL on FIGURE 6. In a preferred embodiment,
support projections 230 are integral with support structure inner region 228.
Support projections 230 also have a support projection body 242 which extends
generally away from inner region 228. Support projection body 242 ends with
terminal area 244. Terminal area 244 may comprise a point, a convex rounded
surface, a concave rounded surface, a flat surface or combinations thereof, or
other. For example, in one embodiment wherein support structure 216 comprises
five support projections, two may have a terminal area 244 that is a point,
one
terminal area may be a convex rounded surface, and two terminal areas may be a
flat surface.
[0075] As shown by FIGURE 4, the bladder 200 encloses the support
structure 216. The bladder 200 can be made of any suitable material known in
the
art including but not limited to plastic, polymers, meltblown or spunblown
material,
cloth, rubber, or coated fabrics. One exemplary embodiment of bladder material
may comprise Stevens polyurethane film; ST 2592. Others may so involve, for
example, ST3380 and ST3382, all of which have various lists of different
characteristic (for example, durometer, permeability, melt point, etc) which
may
variously be considered by those of ordinary skill in the art whenever
implementing
particular embodiments in accordance with the present subject matter.
Similarly,
various thicknesses may be practiced in accordance with the present subject
matter, with some preferred examples falling into a range of about 12 mils to
about 15 mils. Urethane coated nylon is among some of the preferred
embodiment materials while urethane is preferred in some instances because it
inherently permits viewing of the star-shaped insert (or other internal
component)
upon inspection, while urethane coated nylon would not provide such feature.
The
bladder 200 comprises an outer surface 202, an inner surface 204, a length
206, a
height 208, a width 210, and a first end 212 and a second end 214. The bladder
200 may be opaque or clear. In certain embodiments, the bladder 200 has a
column shape but may also have a cigar shape, rectangular, or other shape
known
to those skilled in the art. It is understood that the volume of the bladder
200 will
be calculated based on the shape of the particular embodiment being measured
as
18
CA 02702703 2010-05-04
known to those skilled in the art. For purposes of example only, in instances
where the shape is columnar, volume will be calculated as pi multiplied by the
radius squared multiplied by the length of the column. In rectangular or
square
embodiments, volume is calculated as length multiplied by width multiplied by
height. It is further understood that in some embodiments bladder height and
width may be equal or they may be different, e.g., in ellipsoid shaped
bladders.
Bladder 200 is intended as representing all such variations of the present
subject
matter.
[0076] In one present exemplary embodiment, the support structure first
face 224 contacts bladder first end 212, and support structure second face 226
contacts bladder second end 214. In other embodiments, support structure first
face 224 and second face 226 do not contact bladder first end 212 and bladder
second end 214. In still another embodiments, support structure first face 224
or
second face 226, or both, may comprise support projections 230 which extend
outward from each face to engage bladder first end 212 and bladder second end
214, respectively. Either first end 212 or second end 214 may have a
connection
(not shown) as known to those skilled in the art made with a respective
section of
tubing (not shown). Such air tubing interconnects with the interior of the
bladder to
facilitate initially establishing air pressure therein and/or later adjusting
such
amount of air pressure.
[0077] Alternatively, bladder 200 may be arranged in series with other
bladders with interconnections between bladders 200 to allow air or fluid to
pass
from one bladder 200 to another in response to pressure applied to the patient
support surface. In addition to the numerous support arrangement variations
which may be practiced, including longitudinal, lateral, angular, and mixed
arrangements of single or multiple air or fluid bladders 200, in accordance
with the
present subject matter, it is also to be understood that numerous self-
adjusting
components may be provided in accordance with the present subject matter for
use with various such support arrangements. Further, when bladder 200 is used
in
series with other bladders 200, it is understood that the plurality of
bladders 200
are arranged so that preferably they do not contact one another during various
loading conditions, though contact may be involved in some instances, when the
patient support surface or other embodiment is either loaded or unloaded.
19
CA 02702703 2010-05-04
[0078] In one present exemplary embodiment, the volume of support
structure 216 may comprise substantially all of the volume of bladder 200. In
another embodiment, support structure 216 may comprise 90% or less of the
volume of bladder 200. In other embodiments, support structure 216 may
comprise 80% or less of the volume of bladder 200, 70% or less or even 60% or
less of the volume of bladder 200. In one preferred embodiment, it may
comprise
about 80%. More broadly, as otherwise discussed herein, it is to be understood
by
those of ordinary skill in the art that the present subject matter is intended
as
having a foam-to-air ratio relatively as low as possible while still being
able to have
the foam component to restore the unloaded volume of the tube, which results
in
varying ratios for particular embodiments depending on their specifics.
[0079] The various embodiments of the present subject matter disclosed
herein are used to assist with increasing comfort and stability in patient
support
surfaces using a combination air or fluid filled bladder 200 and internal
support
structure 216. The present subject matter can be used in conjunction with a
method of equalizing pressure over the surface of the body by means of
interconnected air or fluid-filled tubes that shift air or fluid from bladders
under
more pressure to bladders under less pressure. Such functionality allows
greater
immersion of the body into the mattress, which decreases pressure under any
single point, and distributes pressure over as great an area as possible.
[0080] The present subject matter allows the support structure 216 to keep
the bladder 200 expanded by the support projections 230 contacting the inner
surface 204 of the support bladder 200 via terminal area 244. Bladder 200 thus
exerts force upon inner surface 204. Accordingly, bladder 200 does not
collapse if
air pressure in the bladder 200 is reduced. Further, using support structure
216
which contains support structure openings 232, which are defined on either
side by
support projections 230, one is able to use less foam in constructing the
support
structure 216 via incorporation of support structure openings 232.
[0081] Further, support structure openings 232 in support structure 216
provide several distinct advantages over existing systems. Such advantages may
include allowing bladder 200 (which in one exemplary embodiment may be an air
filled bladder containing foam support structure 216) to possess the feel and
support of an air mattress as known to those skilled in the art while also
CA 02702703 2010-05-04
maintaining the benefits of a foam mattress. Such advantageous performance
includes increased structural support as well as protection against the
bladder 200
collapsing when air pressure is removed or if the bladder 200 is punctured.
Additional advantages include that openings 232 serve to allow air or fluid to
move
more freely within the bladder 200 as opposed to existing systems where the
foam
block is a solid construct that essentially fills the interior of the air
cylinder used in
such devices. In the present subject matter, openings 232, or in alternative
embodiments cavity 238 alone or in combination with openings 232, allow air or
fluid to move about in the bladder 200 with less restriction.
[0082] Air or fluid can move within openings 232 or cavity 238 without
necessitating air or fluid flow through the material comprising support
structure
216. Such advantageous functionality prevents slowing air or fluid movement
which in turn slows the ability of the bladder 200 to react to patient
movement or
pressure changes.
[0083] Embodiments of the present subject matter also help overcome the
tendency of existing patient support systems toward "hammocking" wherein
pressure accumulates toward the area of least lateral support, often the
center of a
patient support surface. This results in a hammock effect, which is
uncomfortable
for a person resting on the mattress. Moreover, when air is let out of
existing
patient support systems incorporating only air-filled bladders, the entire
apparatus
collapses and no longer supports the reclining body, the hammock effect being
present all the way down through partial deflation. Such characteristic can be
undesirable in a mattress because each movement of weight, such as found in a
typical person's sleeping pattern, shifts the hammock effect around on the
mattress.
[0084] Use of the present subject matter would be applicable to all manner
of seating arrangements (including partially reclined or angled seating
arrangements such as military vehicles designed to withstand acceleration
shock).
Applicable seating arrangements may include wheelchairs and geriatric care
chairs
of all type. Consumer seating arrangements may also include ergonomic chairs
(such as for office workers) and automobile or transportation vehicle seating
devices of all types. In conjunction with such, there could be a particular
21
CA 02702703 2010-05-04
improvement in rider comfort, especially in long term travel circumstances or
otherwise rough ride circumstances such as in trucks or trains.
10085] It will likewise be understood that multiple bladders 200 in
accordance with the present subject matter may be so arranged (i.e.,
combined),
as desired, in either seating arrangements or mattress or patient support
systems
of virtually all types. In conjunction with medical products, such specialized
mattresses may include mattresses themselves, or mattress overlays, or
mattress
replacement systems. The resulting support systems may be specialized for X-
ray, operating room, or NMR/MRI technology use. Still further, arrangements
thereof may be made for intended use in either intensive care or regular care
settings, including home healthcare or nursing home settings. The present
subject
matter would likewise be applicable to all manner of critical care settings,
as well
as burn patient settings, emergency room gurneys, and ambulance stretchers.
100861 In addition to the many embodiments referenced above, it is to be
further understood that other variations may be practiced so as to combine
different features for obtaining bladders for use in patient support surfaces
and
other supports of types not illustrated. For example, a bladder in accordance
with
present subject matter can be created with uses a low molecular weight liquid
in
association with multiple support structures disposed in a bladder. Further
yet, the
number and method of orienting the bladders may be changed, such as placing
bladders alongside and on top of one another for use in a patient support
surface.
All such variations and modifications are intended to come within the spirit
and
scope of the present subject matter. Therefore, the spirit and scope of the
present
subject matter should not be limited to the description of the exemplary
presently
preferred versions contained herein.
22
