U.S. patent application number 15/392058 was filed with the patent office on 2017-04-20 for positive pressure medical dressings with valve and kits containing same.
The applicant listed for this patent is 3M INNOVATIVE PROPERTIES COMPANY. Invention is credited to Patricia A. Eull, Tony J. Kaufman, Kenneth A. Peterson, Matthew T. Scholz.
Application Number | 20170105879 15/392058 |
Document ID | / |
Family ID | 47883917 |
Filed Date | 2017-04-20 |
United States Patent
Application |
20170105879 |
Kind Code |
A1 |
Scholz; Matthew T. ; et
al. |
April 20, 2017 |
POSITIVE PRESSURE MEDICAL DRESSINGS WITH VALVE AND KITS CONTAINING
SAME
Abstract
Medical dressings and medical dressing kits that can be used to
proved positive pressure wound therapy. The medical dressings
include one or more normally-closed valves. The medical dressing
kits may further include fittings.
Inventors: |
Scholz; Matthew T.;
(Woodbury, MN) ; Eull; Patricia A.; (Mahtomedi,
MN) ; Peterson; Kenneth A.; (White Bear Lake, MN)
; Kaufman; Tony J.; (Rosemount, MN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
3M INNOVATIVE PROPERTIES COMPANY |
St. Paul |
MN |
US |
|
|
Family ID: |
47883917 |
Appl. No.: |
15/392058 |
Filed: |
December 28, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14342572 |
Mar 4, 2014 |
9561134 |
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PCT/US2012/053302 |
Aug 31, 2012 |
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15392058 |
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61534614 |
Sep 14, 2011 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61F 13/00051 20130101;
A61F 13/0226 20130101; A61F 13/023 20130101; A61F 13/00063
20130101; A61F 2013/00174 20130101; A61F 13/0216 20130101; A61F
13/0203 20130101; A61F 2013/00285 20130101 |
International
Class: |
A61F 13/02 20060101
A61F013/02; A61M 35/00 20060101 A61M035/00 |
Claims
1. A medical dressing comprising: a conformable backing having
generally opposed first and second major surfaces, a passage
defined therethrough connecting the first and second major
surfaces, and a perimeter of the second major surface; adhesive
disposed at least proximate to the perimeter of the second major
surface; and a normally-closed one-way flow control valve affixed
to the conformable backing and surrounding the passage
therethrough; wherein the normally-closed one-way flow control
valve permits fluid flow in a first direction from the first major
surface to the second major surface when in an open configuration
and restricts fluid from flowing in a second direction from the
second major surface to the first major surface when in a closed
configuration; and wherein, if the medical dressing is applied over
a treatment site, then the medical dressing defines a
normally-sealed environment over the treatment site.
2. The medical dressing of claim 1, wherein a dead volume between
the normally-closed one-way flow control valve and the conformable
backing is 10 mm.sup.3 or less.
3. The medical dressing of claim 1, wherein the normally-closed
one-way flow control valve comprises an antechamber defining an
external opening, and wherein administration of a pressurized fluid
through the external opening opens the normally-closed one-way flow
control valve.
4. The medical dressing of claim 1, wherein the normally-closed
one-way flow control valve is flexible and may be easily folded in
at least one direction between the thumb and forefinger of a
healthcare worker.
5. The medical dressing of claim 1, further comprising a closure
element attached to the first major surface of the backing and
covering the normally-closed one-way flow control valve, wherein
the closure element seals the normally-closed one-way flow control
valve shut.
5. The medical dressing of claim 1, further comprising an inlet
port adapted for attachment to the first major surface of the
backing over the normally-closed one-way flow control valve.
6. The medical dressing of claim 1, further comprising a barrier
element attached proximate to the second major surface of the
backing.
7. The medical dressing of claim 1, further comprising a septum
element attached to the backing.
8. The medical dressing of claim 1, wherein the normally-closed
one-way flow control valve is constructed of thin films.
9. The medical dressing of claim 8, wherein the normally-closed
one-way flow control valve is constructed to provide a flattened
channel which opens upon pressurization with a pressurized
medicament.
10. The medical dressing of claim 9, wherein the pressurization is
higher than a cracking pressure of the normally-closed one-way flow
control valve.
11. The medical dressing of claim 10, wherein the normally-closed
one-way valve is bonded to the backing.
12. The medical dressing of claim 11, wherein the normally-closed
one-way flow control valve is bonded to the backing using
transverse bonds.
13. The medical dressing according to claim 1, wherein the backing
has a moisture vapor transmission rate of at least 300 g/m.sup.2/24
hrs/37.degree. C./100-10% RH.
14. A medical dressing kit, the kit comprising: a medical dressing
according to claim 1; a closure element attached to the first major
surface of the backing over the normally-closed one-way flow
control valve, wherein the closure element seals the
normally-closed one-way flow control valve shut.
15. The medical dressing kit according to claim 14, further
comprising at least one of: a wound fluid absorbent material, a
medicament reservoir, and combinations thereof.
16. The medical dressing kit according to claim 15, further
comprising at least one of: a pressurized medicament container,
connection means to interface the pressurized medicament container
with the normally-closed one-way flow control valve, and
combinations thereof.
17. A method of treating a wound, the method comprising: applying a
medical dressing according to claim 1 over a wound; introducing a
pressurized fluid medicament into the normally-sealed environment
through a valved opening in the backing.
18. The method according to claim 17, wherein the fluid medicament
introduced into the normally-sealed environment comprises a gas
such that the pressure within the normally-sealed environment is in
a range of from 0.1 mmHg up to 100 mm Hg for a period of at least
one minute.
19. A method according to claim 17, wherein the fluid medicament
introduced into the normally-sealed environment comprises an oxygen
concentration in a range from 21% up to 100%.
20. A method according to claim 17, wherein the fluid medicament
introduced into the normally-sealed environment comprises one of a
nitric oxide, ozone, iodine or hydrogen peroxide.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation application of U.S.
patent application Ser. No. 14/342,572, filed Mar. 4, 2014, which
is a 371 of International PCT/US2012/053302, filed Aug. 31, 2012,
which claims the benefit of U.S. Provisional Patent Application No.
61/534,614, filed Sep. 14, 2011, which is incorporated herein by
reference in its entirety.
BACKGROUND
[0002] Hyperbaric oxygen therapy is well accepted, however, there
can be serious disadvantages with systemic delivery of oxygen.
Elevated systemic oxygen can result in oxygen toxicity leading to
central nervous system issues, pulmonary disease, and seizures.
While external hyperbaric oxygen chambers have been used over the
years to treat the wounds and sores of medical patients, the
following problems have persisted: (1) patient immobility and
potential claustrophobia, (2) lack of portability of the equipment,
(3) excessive cost for purchasing and operating specially designed
oxygen delivery equipment used in conjunction with hyperbaric
chambers. Many attempts have been made to simplify the therapy. For
example, several have suggested using inflatable bags wrapped about
limbs or even the entire lower body. These solutions are still
cumbersome and do not allow patient mobility. Many others have
developed compositions comprising fluids such as perfluorinated
alkanes to deliver oxygen to the tissue. These compositions have
questionable toxicity and wound healing potential.
[0003] There are many other medicaments that can be advantageous to
wound care (e.g., antimicrobial agents, chemotaxis agents, steroids
and other anti-inflammatories, growth promoters, and vasodilators),
that can be delivered in a gas, vapor, or aerosolized phase under
pressure. Conventional therapy requires a procedure of removing a
dressing to access the wound and apply the medicament. This
procedure potentially exposes the wound to contamination, can cause
skin stripping, and is time consuming and costly due to frequent
dressing changes. There is a need for a convenient and safe method
of delivering medicaments to a wound or portion of skin without the
need to remove the dressing.
SUMMARY
[0004] In one aspect, the present disclosure provides a medical
dressing comprising a backing comprising an interior surface and an
exterior surface; adhesive on at least a portion of the interior
surface, wherein the adhesive extends around a perimeter of the
interior surface of the backing to adhere the medical dressing to a
subject over a wound; a normally-closed valve attached to the
backing over an passage formed through the backing, wherein fluid
flow through the passage is controlled by the valve, and wherein a
dead volume between the normally-closed valve and the backing is 10
mm.sup.3 or less; wherein, when the medical dressing is attached
over the wound, the medical dressing defines a normally-sealed
environment over the wound, and further wherein administration of a
pressurized medicament to the external inlet of the valve opens the
normally-closed valve such that fluid within the pressurized
container can be administered to the normally-sealed environment,
and when administration of the pressurized medicament stops, the
valve is allowed to self seal.
[0005] In another aspect, the present disclosure may provide a
medical dressing comprising a backing comprising an interior
surface and an exterior surface; adhesive on at least a portion of
the interior surface, wherein the adhesive extends around a
perimeter of the interior surface of the backing to adhere the
medical dressing to a subject over a wound; a normally-closed valve
attached to the backing over an passage formed through the backing,
wherein fluid flow through the passage is controlled by the valve,
wherein the valve comprises a plurality of polymeric film layers
aligned with the backing when in a closed configuration, and
wherein the plurality of polymeric film layers comprises at least
one flap layer comprising a flap formed therein, wherein the flap
is normally sealed flat against an opposing film but opens in
response to a positive pressure; wherein, when the medical dressing
is attached over the wound, the medical dressing defines a
normally-sealed environment over the wound, and further wherein
application of a positive pressure to the external inlet of the
valve opens the normally-closed valve such that fluid within a
pressurized medicament container can enter the normally-sealed
environment.
[0006] In some embodiments such as those provided above, the
medical dressing further comprises an easy to use connection means
to interface the pressurized medicament container with the valve.
In one embodiment the pressurized container comprises a pressurized
container with a hand operated valve to release the contents. The
contents are expelled through a rigid or semi-rigid tube or straw,
flexible tube, nozzle, or other connection means. In one
embodiment, the connection means is easily connected to the
external surface of the valve on the medical dressing by placing it
through a hole in an antechamber to the valve. The antechamber may
be filled with a filter including a filter capable of removing at
least a portion of contaminating microorganisms.
[0007] In some other embodiments, the medical dressing further
comprises an easy to use connection to interface the medical
dressing with a pressurized container that is larger than a
hand-held container (e.g., a gas cylinder or a house gas supply
system, optionally via an outlet in a wall (or ceiling, or floor)
of a room where a subject is being treated with the medical
dressing), typically connected to the medical dressing by a
quick-connect adapter or other means, and typically including a
regulation valve to adjust the pressure of medicament that
pressurizes the medical dressing. In this embodiment, the
connection between the medical dressing and the pressurized
container may be temporary (e.g., up to a minute, up to 10 seconds,
up to 5 seconds, or even up to 1 second), or the connection between
the medical dressing and the pressurized container may be more
permanent (e.g., more than 1 minute, more than 10 minutes, more
than 1 hour, or even more than 1 day).
[0008] The present disclosure also includes kits of any of the
medical dressings of the present disclosure along with one or more
containers of pressurized medicament which container is adapted to
at least temporarily be connected to the medical dressing in order
to deliver the medicament.
[0009] Any of the above embodiments may also comprise one or more
of the following elements in any combination: a closure element, a
barrier element, wound fluid absorbent material, a connection
means, and a medicament reservoir.
[0010] Methods of treating a wound with the medical dressings of
the present disclosure also are disclosed.
[0011] "Normally-sealed environment" refers to an environment
between a medical dressing and a wound or section of intact skin
over which the dressing is attached, where fluids (and solids) from
the ambient atmosphere surrounding the exterior of the medical
dressing cannot freely enter.
[0012] "Treatment site" refers to a wound or other portion of skin
to be treated. "Preferred" and "preferably" refer to embodiments of
the disclosure that may afford certain benefits, under certain
circumstances. However, other embodiments may also be preferred,
under the same or other circumstances. Furthermore, the recitation
of one or more preferred embodiments does not imply that other
embodiments are not useful, and is not intended to exclude other
embodiments from the scope of the disclosure.
[0013] As used herein, "a," "an," "the," "at least one," and "one
or more" are used interchangeably. The term "and/or" means one or
all of the listed elements/features or a combination of any two or
more of the listed elements/features.
[0014] The above summary is not intended to describe each
embodiment or every implementation of the present invention.
Rather, a more complete understanding of the invention will become
apparent and appreciated by reference to the following Description
of Exemplary Embodiments and claims in view of the accompanying
figures of the drawing.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 is a cross-sectional view of an exemplary embodiment
of a medical dressing of the present disclosure.
[0016] FIG. 2 is cutaway perspective view of an exemplary
embodiment of a medical dressing of the present disclosure.
[0017] FIGS. 3A, 3B, and 3C are cross-sectional views of exemplary
embodiments of medical dressings of the present disclosure.
[0018] FIG. 4 is a schematic plan view of an exemplary embodiment
of a normally-closed one-way flow control valve of the present
disclosure.
[0019] FIGS. 5A and 5B are cross-sectional views of an exemplary
embodiment of a normally-closed one-way flow control valve of the
present disclosure.
[0020] FIG. 6 is a schematic plan view of an exemplary embodiment
of a normally-closed one-way flow control valve of the present
disclosure.
[0021] FIG. 7 is a schematic cross-sectional view of an exemplary
embodiment of a normally-closed one-way flow control valve of the
present disclosure.
[0022] FIGS. 8A and 8B are schematic cross-sectional views of an
exemplary embodiment of a normally-closed one-way flow control
valve of the present disclosure.
[0023] FIG. 9 is a schematic plan view of an exemplary embodiment
of a medical dressing of the present disclosure.
DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0024] In the following description of exemplary embodiments of the
disclosure, reference is made to the accompanying figures of the
drawing which form a part hereof, and in which are shown, by way of
illustration, specific embodiments in which the disclosure may be
practiced. It is to be understood that other embodiments may be
utilized and structural changes may be made without departing from
the scope of the present disclosure.
[0025] One exemplary embodiment of a medical dressing 100 is
depicted in FIGS. 1 and 2, where FIG. 1 is a cross-sectional view
the medical dressing 100, and FIG. 2 is cutaway perspective view of
the medical dressing 100. Medical dressing 100 includes backing 110
(which may preferably be conformable as described herein). Backing
110 includes two opposed major surfaces: interior surface 122 and
exterior surface 124. In use, interior surface 122 faces a wound
(or other body site) over which the dressing is placed while
exterior surface 124 faces away from the wound (or other body
site).
[0026] Potentially suitable materials for backing 110 are described
in more detail below, but functionally, backing 110 is preferably
made of materials that serve as a barrier to bacteria, has a high
moisture vapor transmission rate but is at least a temporary
barrier to rapid diffusion of the medicament. The barrier
properties of backing 110 may or may not be absolute. For example,
backing 110 may allow for limited passage of gas, although backing
110 (and the other components of medical dressing 100) preferably
provides sufficient barrier properties to the passage of the
medicament such that, when placed over a wound, a positive pressure
environment can be at least temporarily maintained above a wound.
For example, the backing 110 may preferably have relatively high
moisture vapor transmission rates, but be substantially impervious
to liquids.
[0027] The medical dressings of the disclosure may be soft and
conformable such that they provide a reduced likelihood of creating
a pressure point that could cause wound damage if a patient were
lying on the portion of the dressing for prolonged periods of time
(e.g., for two hours or more).
[0028] Medical dressing 100 further includes normally-closed
one-way flow control valve 150 that is affixed to backing 110 over
one or more passages 170 that are formed through backing 110. Fluid
flow through the one or more passages 170 in backing 110 is
controlled by normally-closed one-way flow control valve 150.
Normally-closed one-way flow control valve 150 (preferably, a
self-sealing valve) may be used to administer a medicament under
positive pressure to a wound (or intact skin area) over which
dressing 100 is placed as described herein. The medical dressings
of the present disclosure may include more than one normally-closed
one-way flow control valve, or other additional valve(s), if
additional access to the normally-sealed environment defined by the
dressing is desired.
[0029] Medical dressing 100 may also include adhesive 120 on
interior surface 122 such that medical dressing 100 can be adhered
to a subject over a wound with interior surface 122 facing a wound.
Adhesive 120 may cover all or part of interior surface 122 in a
continuous, discontinuous, and/or pattern coated fashion. Adhesive
120 in FIGS. 1 and 2 is depicted only around perimeter 140 of the
dressing. In other embodiments the adhesive covers interior surface
122 more completely, or even completely. Importantly, in many
embodiments adhesive 120 seals dressing 100 to the skin preventing
rapid escape of the medicament administered. In addition, adhesive
120 may include one or more adhesives. Adhesive 120 may contain an
optional medicament in the adhesive or on the surface of the
adhesive.
[0030] Adhesive 120 in the exemplary embodiment depicted in FIG. 1
is provided only around perimeter (i.e., border) 140 of backing 110
such that adhesive 120 forms a frame around a central part of
interior surface 122 of backing 110. One arrangement places
dressing 100 over a wound while adhesive 120 is attached to the
tissue (e.g., skin) surrounding the wound or skin location. Medical
dressing 100, along with the wound and the tissue surrounding the
wound, preferably define a normally-sealed environment in which the
wound is isolated from the surrounding environment. Once the
medicament is administered the backing may inflate. Medical
dressing 100 in FIGS. 1 and 2 is shown in an inflated condition.
Interior surface 122 of backing 110 faces the normally-sealed
environment in which the wound is located while exterior surface
124 of backing 110 faces away from the wound.
[0031] Adhesive 120 may preferably be exposed on only a portion of
interior surface 122 of backing 110. In the embodiment depicted in
FIGS. 1 and 2, adhesive 120 is provided on only a portion of
interior surface 122 (i.e., the central portion of interior surface
122 is free of adhesive 120). In other embodiments, however,
adhesive may be provided over substantially all of interior surface
122 with a portion of the adhesive covered by another element such
that only a portion of the adhesive remains exposed for attachment
to a subject.
[0032] In any embodiment, however, it may be preferred that
adhesive 120 extend continuously around perimeter 140 of backing
110 such that medical dressing 100, when attached to a subject, can
form a normally-sealed environment over a wound, with the bounds of
the normally-sealed environment being defined by interior surface
122 of backing 110 as adhered to the subject over a wound or skin
site by adhesive 120.
[0033] As shown in FIGS. 1 and 2, medical dressing 100 is typically
provided with release liner 130 to protect adhesive 120 prior to
application over a wound. Release liner 130 is typically removed
prior to application of medical dressing 100 over a wound.
[0034] Referring again to FIGS. 1 and 2, with the use of a suitable
normally-closed one-way flow control valve 150, the normally-sealed
environment created by a dressing 100 attached over a wound may
preferably be maintained at a positive pressure (i.e., pressure
above the ambient atmospheric pressure on exterior surface 124 of
backing 110). The positive pressure is often referred to as the
gauge pressure. Suitable gauge pressure would be just enough to
inflate the dressing or dressing reservoir. The positive pressure
may range from 0.01 mmHg to 700 mmHg. Typically the inflated
pressure immediately after inflation is at least 0.1 mmHg,
preferably as least 1 mmHg. The upper limit is determined by the
integrity of the dressing seal and/or the materials used to
construct the dressing and any reservoir present. The pressure
should not be so high that the dressing seal is compromised or that
excessive pressure is placed on the wound which may delay wound
healing.
[0035] Typically, the inflation pressure will not exceed 500 mmHg
and may not exceed 400 mmHg or even 200 mmHg or even 100 mmHg. In
some embodiments a highly porous spacer may be placed in the
reservoir to maintain the reservoir volume. In this design a
positive pressure within the reservoir may not be necessary. Thus,
the medicament may be placed in the chamber but not in a
pressurized condition, i.e. the pressure within the reservoir is
essentially the same as that of the exterior ambient condition.
Suitable spacers include highly porous materials such as nonwovens,
foams, particle networks, and the like. In this embodiment it may
be beneficial to include an exit valve that opens to allow the
medicament to be flushed through the cavity. The exit valve like
the inlet valve is preferably low profile and flexible and may be
self sealing. Alternatively, the exit port may be simply an
adhesive tab covering an opening which is opened when filling the
medicament reservoir.
[0036] Another method of filling an ambient pressure reservoir with
resilient spacer would be to provide the dressing in a compressed
state that can be inflated with the medicament.
[0037] It may be preferred that the valves be capable of being used
one, two or more times to administer gaseous and/or aerosol
medicament fluids to the normally-sealed environment and/or
reservoir. For example, fluid can be administered to the
normally-sealed environment through the valve as described herein,
with the valve opening by communicating with the pressurized
medicament source and being allowed to close when the pressurized
medicament administration terminates. As the positive pressure
(inflation) deteriorates, it can be simply re-inflated through the
valve as described herein.
[0038] In some embodiments, the medical dressing includes absorbent
material to absorb fluids (e.g., liquids) entering the
normally-sealed environment. Examples of potentially suitable
absorbent materials may include hydrocolloids, hydrogels,
hydrophilic foams, woven materials, nonwoven materials, absorbent
fiber fabrics, absorbent films, and combinations thereof. The
absorbent material may be both absorbent and capable of releasing
any optional medicament contained therein which may be the same or
different from that administered under pressure.
[0039] Kits also are possible where a wound absorbent or contact
layer is placed over or in the wound followed by application of the
dressing and finally inflation with the medicament.
[0040] Although the magnitude of the positive pressure maintained
in the normally-sealed environment by dressing 100 will typically
deteriorate over time (after reaching a maximum during
administration of medicament fluids to the normally-sealed
environment and/or reservoir through normally-closed one-way flow
control valve 150), it may be preferred that medical dressing 100
be capable of maintaining the positive pressure for at least some
significant period of time. In some embodiments, it may be
preferred that medical dressing 100 be capable of maintaining at
least some level of positive pressure in the normally-sealed
environment (in the absence of active vacuum source) for a period
of 1 minute or more, 5 minutes or more, 10 minutes or more, 15
minutes or more, 30 minutes or more, or even 60 minutes or
more.
[0041] In some embodiments, normally-closed one-way flow control
valve 150 is formed from multiple film layers such as those
described in U.S. Pat. Nos. 4,674,532, 4,917,646, 5,017,254, and
5,188,558. Another type of normally-closed one-way flow control
valve is described in U.S. Pat. No. 4,842,007. These patents are
incorporated herein by reference. A particularly preferred
normally-closed one-way flow control valve is that incorporated
into ANAGRAM MYLAR 18 INCH DIAMETER BALLOONS (Anagram
International, Inc., a division of Amscan, Inc., Eden Prairie,
Minn.). Self sealing flat valves of this type are disclosed in U.S.
Pat. Nos. 5,378,299 and 5,248,275.
[0042] The base layer of normally-closed one-way flow control valve
150 may be attached to the backing 110 by any suitable technique or
combination of techniques (e.g., adhesives, heat sealing, chemical
welding, thermal welding, ultrasonic welding). In a one embodiment,
backing 110 serves as the base layer of normally-closed one-way
flow control valve 150. In a another embodiment normally-closed
one-way flow control valve 150 is formed as a separate component,
including a base layer, and the base layer of the valve is attached
to backing 110 by a suitable adhesive or heat seal.
[0043] Transformation of normally-closed one-way flow control valve
150 between the open and closed configurations may be performed
selectively, although it may be that normally-closed one-way flow
control valve 150 is normally closed such that, in the absence of
an applied external force capable of opening normally-closed
one-way flow control valve 150, normally-closed one-way flow
control valve 150 is closed. The valves may be self-sealing and
inflation of the chamber results in a force that may assist in
closing the valve. In some embodiments, normally-closed one-way
flow control valve 150 may be opened by a pressure differential
placed across the valve. For example, normally-closed one-way flow
control valve 150 may be opened when the fluid medicament pressure
on the side of normally-closed one-way flow control valve 150
facing in the same direction as exterior surface 124 is
sufficiently larger than the forces operating on the valve to
retain it in the closed configuration. The pressure differential at
which the valve moves from the closed configuration to the open
configuration may be referred to as the "cracking pressure". The
cracking pressure of these self-sealing valves may be a function of
the inflation pressure. The cracking pressure will be greater than
the internal inflation pressure.
[0044] The pressure differential across the valve may be achieved
by connecting a pressurized medicament source. For example, the
medicament source may be a can of pressurized oxygen. For example,
Just Oxygen (Oxygen Bar Party, Los Alamitos Calif.) is a small can
of oxygen that delivers a total of 8 liters of pure oxygen. This
would be sufficient to inflate and re-inflate a dressing multiple
times. The valve on the pressurized medicament container may have a
straw as is common on spray lubricants such as WD-40 (WD-40
Company, San Diego, Calif.). Alternatively, the valve on the
pressurized container may have a fixed means of easily
communicating with and delivering the medicament through the
valve.
[0045] Medical dressing 100 can include optional exit valve 190
over optional exit passage 175 defined through backing 110, wherein
optional exit valve 190 is normally closed, but under
pressurization from interior space 160 optional exit valve 190 can
open to permit fluid to be withdrawn from medical dressing 100
through optional exit passage 175. Optional exit valve 190 is
preferably a one way out valve such as those described in U.S.
patent application Ser. No. 12/936,273, which is incorporated by
reference herein for this purpose.
[0046] FIG. 3A shows an embodiment of medical dressing 300, which
resembles medical dressing 100, having backing 310 with interior
surface 322 opposing exterior surface 324, normally-closed one-way
flow control valve 350 affixed to backing 310 over one or more
passages 370, perimeter 340, adhesive 320, optional liner 330, and
optional exit valve 390 (over optional exit passage 375), but
further comprises film layer 325 affixed to perimeter 340 of
backing 310, forming a reservoir (or "pocket") 360 between film
layer 325 and backing 310. Reservoir 360 so formed can be filled
with a medicament through normally-closed one-way flow control
valve 350 affixed to backing 310. Importantly, film layer 325 is
permeable to the medicament. For example, when the medicament is
oxygen the film layer 325 (and any adhesive which may be present)
should be permeable to the medicament (oxygen). While reservoir 360
appears as a single compartment it may be segregated into multiple
smaller compartments in communication in order to minimize
expansion or "pillowing" of the dressing after inflation. Suitable
oxygen permeable films for film layer 325 include thermoplastic
polymers, thermoset polymers and laminates thereof. Both
thermoplastic and thermoset films may optionally contain fillers,
plasticizers, tackifiers and other additives which may alter the
permeability. Suitable films include polyurethanes, polyolefins
including polyethylene and polypropylene, modified celluloses such
as cellulose esters including but not limited to cellulose acetate,
polyacrylates, aromatic and aliphatic polyesters (e.g., PET, PETG,
polylactic acid, polybutylene terephthalate), silicones, block
copolymers (e.g., SIS, SBS) and those available from Kraton
Polymers Inc., polyvinylidene chloride, fluorinated polymer films
including polytetrafluorethylene (Teflon) and
poly(chlorotrifluoro)ethylene (Kel F). It is understood that film
layer 325 also may be a microporous film to allow very rapid
transport of the medicament. The pores of the microporous film may
or may not be filled with a second polymer. Aerosol medicaments may
require film layer 325 to be a microporous membrane in order to
have sufficient diffusion rate. Suitable microporous membranes
include gas-permeable but liquid-resistant microporous membranes
which may be formed by a number of different processes including
solvent casting, thermally induced phase separation, exposing the
membrane to radiation that weakens the plastic and creates specific
areas that can be removed by dousing the membrane in acid (or other
chemicals), stretching or expanding films and the like. Supporting
nonwovens or other fabrics may be attached to the membrane to
provide support. In one embodiment, the microporous material is an
expanded PTFE material having a polyester, polyethylene or
polypropylene mesh support which facilitates attachment.
[0047] In some embodiments, film layer 325 is molecularly permeable
to the medicament. In some embodiments, the permeability may be
used to control the rate of delivery. For example, in the case of
the use of oxygen as a medicament film layer 325 is permeable to
oxygen but remains impermeable to other materials (e.g., wound
fluids, bacteria, or virus) and is highly permeable to allow rapid
delivery of the oxygen. In the case of nitric oxide (NO), the gas
delivered is a dilute solution of NO and film layer 325 may be
slightly permeable to NO to control the rate of delivery.
[0048] Note that in certain embodiments it may be desirable to
administer more than one medicament to a treatment site. This can
be done by incorporating multiple reservoirs to which medicaments
may be administered, administering said medicaments to a single
reservoir or dressing, or administering one or more medicaments to
the reservoir and one or more medicaments to the normally-sealed
treatment site. Thus, each reservoir would have a valve through
which a medicament can be administered and the dressing may
optionally comprise a valve communicating directly to the
normally-sealed treatment site. While shown as a single reservoir
360 in FIG. 3A, it is understood that one, two, three or more
reservoirs may be present. The films or membranes of film layer 325
may be treated on one or both sides to make the film hydrophobic or
hydrophilic. For example, to transport an aqueous aerosolized
medicament through the film layer 325 it may be advantageous to
provide a hydrophilic film that is easily wetted by the aqueous
phase of the aerosol.
[0049] Note that FIG. 3A has depicted reservoir 360 above film
layer 325. Alternatively, or additionally, an inflatable reservoir
may be placed beneath film layer 325, in optional region 329.
[0050] FIG. 3B is a cross-sectional view of an exemplary embodiment
of medical dressing 301 of the present disclosure, similar to
medical dressing 300 except that adhesive 321 is provided on film
layer 325, covering all or part of film layer 325 in a continuous
and/or patterned fashion.
[0051] FIG. 3C is an exemplary embodiment of medical dressing 302,
similar to medical dressing 301 but including absorbent layer 380
between film layer 325 and adhesive layer 321. Optional film layer
327 is also shown in FIG. 3C, which can be useful in embodiments
where absorbent layer 380 is beneficially held in place. In some
embodiments, absorbent layer 380 has sufficient structural
integrity (e.g., as in the case of some foams) so that optional
film layer 327 may not be required. If optional film layer 327 is
included, it should be permeable to the medicament, as described
for film layer 325. Normally-closed one-way flow control valve 150
(or 350) used in the medical dressings of the disclosure may be
soft and conformable such that it provides reduced likelihood of
creating a pressure point that could cause wound damage if a
patient were lying on the portion of the dressing containing the
valve for prolonged periods of time (e.g., for two hours or more).
The normally-closed one-way flow control valves may be so
conformable that the valve, even as attached to the dressing, can
be manually folded over between the thumb and the forefinger of a
person such as a healthcare worker in at least one direction and
preferably in multiple directions. Normally-closed one-way flow
control valves may recover fully from folding. In some embodiments,
normally-closed one-way flow control valves are drapable (i.e.,
they bend over under their own weight). Drapable valves comprise a
laminate of at least two film layers.
[0052] FIG. 4 shows an exemplary embodiment of a normally-closed
one-way flow control valve 400 having valve reed 450 that defines
valve inlet 440, antechamber 425 that defines instillation port
410, and exit chamber 470 that defines valve outlet 460. Valve reed
450 communicates with antechamber 425 through valve inlet 440, and
valve reed 450 is typically in fluid communication with interior
surface 122 of medical dressing 100 through valve outlet 460, which
is typically aligned with one or more passages 170 in backing 110.
Valve reed 450 has, in addition to valve inlet 440, antechamber
reed portion 456 and exit chamber reed portion 457. A bond is
provided along perimeter bond 433 that bonds together the several
layers of the normally-closed one-way flow control valve (e.g., by
ultrasonic welding or heat-sealing), as is evident in the
cross-sectional views in FIGS. 5A and 5B (taken along "5A" in FIG.
4). Transverse bonds 490 and 491 provide additional bonding of the
several layers of the normally-closed one-way flow control valve.
It will be noted that valve reed 450 is not bonded together at
valve inlet 440. During a bonding process to provide transverse
bonds 490 and 491, a temporary spacer element (not shown) may be
provided in valve inlet 440, to keep valve inlet 440 from being
bonded closed, and subsequently the temporary spacer element (not
shown) is removed from valve inlet 440. Optionally, normally-closed
one-way flow control valve 400 includes a film portion 435
surrounding all or part of the perimeter bond 433.
[0053] Antechamber 425 may have a height of 2-20 mm or more.
Antechamber 425 serves to provide a visual queue to where the
medicament should be instilled and may facilitate installation of
normally-closed one-way flow control valve 400. Medicament is
instilled through instillation port 410. Optionally, support
material 420 (a foam, nonwoven or other resilient porous material)
is provided, and in some embodiments support material 420 serves to
keep the antechamber 425 open to facilitate insertion of, for
example, an inflation tube or straw.
[0054] Antechamber 425 is in fluid communication with valve reed
450 to facilitate delivery of the medicament. For example,
antechamber 425 may include a resilient foam filled bulb 430
comprising an elastomeric film and defining instillation port 410.
In some embodiments, instillation port 410 is designed to be
slightly smaller in diameter than a straw or inflation tube through
which medicament passes from a pressurized container. When the
straw or inflation tube is placed through instillation port 410
into antechamber 425, the elastomeric film of resilient foam filled
bulb 430 seals around the straw, providing a seal.
[0055] FIG. 5A is a cross-sectional view (taken along "5A" in FIG.
4) of an exemplary embodiment of normally-closed one-way flow
control valve 400. Normally-closed one-way flow control valve 400
includes film layers 401 and 402 bonded (e.g., by ultrasonic
welding or heat-sealing) along peripheral bond 433, enclosing valve
reed 450 as well as optional support material 420. In some
embodiments, film layer 402 can optionally be part of the dressing
construction (e.g., a portion of backing 110 can serve as the "base
layer" of normally-closed one-way flow control valve 400).
[0056] Valve reed 450 can be formed, for example, by ultrasonic
welding or heat-sealing a perimeter of two valve reed film layers
451 and 452 (e.g., along the portions of 450 that lies along
perimeter bond 433 and transverse bonds 490 in FIG. 4), excepting
that portion of the perimeter where valve inlet 440 exists. It will
be noted that valve reed film layers 451 and 452 are not bonded
together at valve inlet 440, and also are not bonded together at
those portions that do not lie along any perimeter bonds, to allow
for fluid communication between antechamber 425 and exit chamber
470. Preferably, valve reed film layers 451 and 452 are flexible
and flat to ensure that valve reed film layers 451 and 452
reversibly "seal" together to permit retention of medicament in
medical dressings of the present disclosure, but do not excessively
"block" together (i.e., bond tightly enough to resist instillation
of pressurized medicament), which may cause the valve not to
open.
[0057] In FIG. 5A, valve reed 450 is shown with valve reed film
layers 451 and 452 in contact with each other (i.e., valve reed
passage 455 is in a "sealed" condition). In FIG. 5B, valve reed
film layers 451 and 452 are shown parted (i.e., valve reed passage
455 is in an "open" condition), as would occur during instillation
of the medicament from pressurized container (not shown).
[0058] As discussed herein, it may be preferred that the profile or
height of the valves be limited to improve patient comfort and
increase resistance to displacement by external forces (e.g., from
bedding or clothing) For example, the preferred valves are
virtually undetected when a patient lies on them when sleeping on a
mattress. The low profile valves may also improve patient comfort
where, for example, the medical dressing is placed in a location on
which the patient's weight rests while sitting, lying, and/or
standing.
[0059] One manner in which the low-profile valves used in
connection with the medical dressings can be characterized may be
in terms of maximum of the valve structure as measured normal to
the major surfaces of the backing (where the major surfaces of the
backing are the interior surface and the exterior surface). It may
be preferred, for example, that the valves used in the medical
dressings have a maximum thickness (not including optional
resilient foam filled bulb 430) of 3 millimeters or less, in some
embodiments 2 millimeters or less, or even 1 millimeter or less,
and more preferably 0.5 millimeter or less (e.g., even 200
micrometers or less) in a non-pressurized condition on a flat
surface. Films used to make these valves typically have a thickness
less than 250 micrometers, preferably less than 150 micrometers,
more preferably less than 125 micrometers. The films used to make
the valves typically have a thickness of at least 25 micrometers
and preferably at least 50 micrometers.
[0060] Another manner in which the low-profile valves can be
characterized may be in the form of dead volume between the
normally-closed valve and the backing. As used herein, the term
"dead volume" refers to the volume or space in which fluids may
accumulate between the valve and the interior surface of the
backing when the valve is in its normally-closed configuration
(i.e., that volume or space within exit chamber 470 in FIG. 5A).
Reducing the dead volume between the normally-closed valve and the
interior surface of the backing can help to reduce the profile of
the valve and the dressing as a whole.
[0061] The dead volume defined by a normally-closed valve and
backing in a medical dressing of the present disclosure may
preferably be 10 cubic millimeters (mm.sup.3) or less, in some
embodiments 6 mm.sup.3 or less, or even 4 mm.sup.3 or less, and
further, in some embodiments, even 2 mm.sup.3 or less (e.g., 1
mm.sup.3 or less). In the some embodiments the valves are designed
to have essentially no dead volume since they form a film/film
seal. It is understood that some very small dead volume will exist
but it is less than about 0.2 mm.sup.3. Dead volume is measured
with the valve in a relaxed state with no inflation in the
dressing. The valve may be incorporated into a port or tubing
connection, however, elastomeric tubing can form a relatively rigid
structures can cause pressure points when the patient is lying on
the wound, for example, when in bed. Thus, if tubing is used it
should be soft and relatively easy to collapse in order to prevent
pressure point formation. So called "lay-flat" tubing with a valve
may be used. In a tubing valve a duck bill check valve may be used
that is a one way valve allowing medicament into the dressing but
not allowing the pressurized gas or aerosol to escape. Suitable
examples of duck bill check valves include those available from
Vernay Laboratories, Inc. (Yellow Springs, Ohio).
[0062] Another optional element that may be included with the
medical dressings are filter elements that may be placed proximate
the valve(s) of the medical dressings or on the medicament delivery
container or both. The filter elements may function to filter
materials which may be present in the medicament container (e.g.,
bacteria, virus, or spores) which should not enter the
normally-sealed environments defined by the medical dressings. The
filter elements may be provided attached to the medical dressings
proximate the exterior valve surfaces of the backings of the
medical dressings. For example, as shown in FIG. 4, support
material 420 within antechamber 425 can function to filter the
inbound medicament. The filter elements may be provided using a
variety of different materials. Examples of some potentially
suitable materials for the filter elements may include fabrics
(e.g., gauze, nonwoven fabrics, woven fabrics, knitted fabrics),
foams, porous membranes, and laminates thereof.
[0063] FIG. 6 shows an exemplary embodiment of a flat film
normally-closed one-way flow control valve 600 having valve reed
650 extending from antechamber 630 through valve inlet 640 to exit
chamber 670. Valve reed 650 is a flat tube. Valve reed 650 can be
formed, for example, by ultrasonic welding or heat-sealing together
two pieces of flat film along valve reed edges 653 and 654.
Preferably, the film used for valve reed 650 is flexible and flat
to ensure that layers reversibly "seal", but do not excessively
"block" together, which may cause the valve reed not to open.
[0064] FIG. 7 is a cross-sectional view (taken along "7" in FIG. 6)
of normally-closed one-way flow control valve 600. Normally-closed
one-way flow control valve 600 includes upper and lower film layers
601 and 602, respectively, bonded (e.g., by ultrasonic welding or
heat-sealing) along peripheral bond 633 and enclosing valve reed
650 as well as optional filtration material (not shown). In some
embodiments, lower film layer 602 can optionally be part of the
dressing construction (e.g., a portion of backing 110). Otherwise
the valve 600 is sealed to the dressing using a thermal weld or an
adhesive taking care to allow the exit port 660 communicate with
the interior of the dressing. Optionally, filter elements may be
placed in the antechamber or wound chamber to filter the medicament
as it passes through the valve into the dressing.
[0065] Valve reed 650 comprises two valve reed film layers 651 and
652. Valve reed film layer 651 is bonded to upper film layer 601
along bond 690, and valve reed film layer 652 is bonded to lower
film layer 602 along bond 691. Valve inlet 640 is not bonded shut.
In this manner, two zones are created, inlet antechamber 630 and
exit chamber 670 and the only way medicament may pass between
antechamber 630 and exit chamber 670 is to pass through reed 650 at
valve inlet 640. Inlet port 610 is defined in antechamber 630.
Inlet port 610 may fit snugly to a pressurized container, however,
it has been observed that if the volume flow of medicament is
sufficient from the pressurized container then a snug fit is not
necessary. The critical requirement is that the pressure generated
must exceed the cracking pressure of the valve reed. Exit port 660
is provided in lower film 602 which will communicate with a backing
of a medical dressing of the present disclosure.
[0066] Shown in FIG. 8A is a cross-sectional view of
normally-closed one-way flow control valve 600 affixed to backing
110. Valve reed 650 is shown with valve reed film layers 651 and
652 in contact with each other at valve reed passage 655 in a
sealed condition. In FIG. 8B, valve reed film layers 651 and 652
are shown parted as would occur during instillation of the
medicament from pressurized container 10 through straw 20 (i.e.,
valve reed passage 655 is "open"). Medicament must pass through
valve reed 650 to get from the antechamber 630 to dressing side
exit chamber 670. There is an inlet port 610 formed in upper film
601 and an exit port 660 in the dressing side film 602. If desired,
film 602 may be an integral part of backing 110.
[0067] Antechambers may take on other forms. For example, when a
flat film valve is used, the antechamber may simply be a tube (not
shown) into which medicament delivery straw 20 is placed. The tube
can optionally contain a filter element (not shown). Straw 20 may
or may not form a seal with the antechamber so long as the pressure
and volume are sufficient to open the valve and at least partially
fill the chamber. If the cracking pressure of the valve is
sufficiently low, the rapidly released pressurized medicament will
open the valve and inflate the dressing.
[0068] Many medicaments may be delivered as a gas or aerosol. As
used herein an aerosol refers to a gaseous suspension of fine solid
particles or liquid droplets. A combination also is possible in
which the gas phase is a medicament such as oxygen. Suitable
gaseous medicaments include gaseous oxygen in concentrations of
21-100% in an inert or active carrier, as well as dilute
concentrations of chlorine, bromine, ozone, nitric oxide, and the
like. Diluents for the medicaments may be any suitable gas such as
a noble gas (nitrogen, argon), helium, air, oxygen and the like.
When oxygen is the medicament preferably it is presented at a
concentration in the gas of greater than 30% w/w, more preferably
greater than 50%, and even more preferably greater than 75% w/w. In
one preferred embodiment the oxygen delivered is present at a
concentration of greater than 90%, preferably greater than 95% and
most preferably greater than 98% w/w. The concentration of these
agents must be adjusted to give a therapeutic effect (e.g.,
antibacterial activity, improved wound healing). The concentration
can be diluted in a suitable carrier gas such as an inert gas (e.g.
nitrogen or argon). Combinations of medicaments also are possible
(e.g., a combination of oxygen and nitric oxide, or a combination
of oxygen and ozone).
[0069] Aerosol medicaments can be many and may include
antimicrobial agents, an antiseptic, an antibiotic, an analgesic, a
vitamin, a steroid, a growth factor, a hormone, a nutrient, or
chemotactic agents. A list of other possible medicaments that may
be delivered in an aerosol form include heparin, covalent heparin,
or another thrombin inhibitor, hirudin, hirulog, argatroban,
D-phenylalanyl-L-poly-L-arginyl chloromethyl ketone, or another
antithrombogenic agent, or mixtures thereof; urokinase,
streptokinase, a tissue plasminogen activator, or another
thrombolytic agent, or mixtures thereof; a fibrinolytic agent; a
vasospasm inhibitor; a calcium channel blocker, a nitrate, nitric
oxide, a nitric oxide promoter or another vasodilator; an
antimicrobial agent or antibiotic; analgesics such as aspirin,
methyl salicylate, camphor, menthol, a lower alcohol such as
ethanol or isopropanol; local anesthetics such as lidocaine,
benzocaine, priolocane, mixtures of these such as EMLA and the
like; ticlopidine, a glycoprotein IIb/IIIa inhibitor or another
inhibitor of surface glycoprotein receptors, or another
antiplatelet agent; colchicine or another antimitotic, or another
microtubule inhibitor, dimethyl sulfoxide (DMSO), a retinoid or
another antisecretory agent; cytochalasin or another actin
inhibitor; or a remodeling inhibitor; deoxyribonucleic acid, an
antisense nucleotide or another agent for molecular genetic
intervention; methotrexate or another antimetabolite or
antiproliferative agent; tamoxifen citrate, paclitaxel ("TAXOL") or
derivatives thereof, or other anti-cancer chemotherapeutic agents;
dexamethasone, dexamethasone sodium phosphate, dexamethasone
acetate or another dexamethasone derivative, or another
anti-inflammatory steroid or non-steroidal anti-inflammatory agent;
cyclosporin or another immunosuppressive agent; trapidal (a PDGF
antagonist), angiogenin, angiopeptin (a growth hormone antagonist),
a growth factor or an anti-growth factor antibody, or another
growth factor antagonist; dopamine, bromocriptine mesylate,
pergolide mesylate or another dopamine agonist; iodine-containing
compounds; a peptide, a protein, an enzyme, an extracellular matrix
component, a cellular component or another biologic agent;
captopril, enalapril or another angiotensin converting enzyme (ACE)
inhibitor; ascorbic acid, alpha tocopherol, superoxide dismutase,
deferoxamine, a 21-amino steroid (lasaroid) or another free radical
scavenger, iron chelator or antioxidant; estrogen or another sex
hormone; AZT or other antipolymerases; acyclovir, famciclovir,
rimantadine hydrochloride, ganciclovir sodium or other antiviral
agents; 5-aminolevulinic acid, meta-tetrahydroxyphenylchlorin,
hexadecafluoro zinc phthalocyanine, tetramethyl hematoporphyrin,
rhodamine 123 or other photodynamic therapy agents; an IgG2 Kappa
antibody against Pseudomonas aeruginosa exotoxin A and reactive
with A431 epidermoid carcinoma cells, monoclonal antibody against
the noradrenergic enzyme dopamine beta-hydroxylase conjugated to
saporin or other antibody targeted therapy agents; gene therapy
agents; and enalapril and other prodrugs, or a mixture of any of
these. Examples of other potentially suitable agents may be
described in U.S. Pat. No. 6,867,342. Medical dressings of the
present disclosure may be particularly suited for treating post
operative surgical wounds. The medical dressings also may be suited
for treating infected tissue and spaces such as abscesses, an
infected peritoneal cavity (peritonitis), topical impetigo and the
like. In this manner, the tissue is treated while containing the
pathogenic organism. These applications may require a relatively
small dressing for an abscess (e.g. less than 7.5 cm square) to
very large dressings/drapes for applications such as peritonitis.
Treatment of peritonitis may include performing a lavage with a
liquid medicament such as an antibiotic solution, saline,
hypertonic saline, an antiseptic solution etc. through the valve
into the dressing with subsequent or simultaneous withdrawal of
fluid through an exit valve. The exit valve is preferably a one way
out valve such as those described in U.S. Published Patent
Application No. 2011/0106030, which is incorporated by reference
herein for this purpose. For large applications (e.g., treatment of
peritonitis) it is also possible to take a small valve dressing the
present disclosure and place it over a larger dressing or an
adhesive coated drape (e.g., and incise drape such that available
from 3M Company, Maplewood Minn., under the trade designation
"IOBAN II") after making a small hole in the dressing or drape so
that the dressing can communicate with the tissue.
[0070] In certain applications the medicament may be colored to
indicate to the clinician or user that the medicament has been
delivered which can be visualized through a transparent dressing.
Alternatively, the dressing or a dressing component could change
color in response to the introduction of medicament. For example,
the dressing could have one or more pH sensitive dyes that change
color with the introduction of a medicament that alters the pH for
example, by inclusion of carbon dioxide which will form carbonic
acid.
[0071] If delivered, an active agent (or agents) could be supplied
to the normally-sealed environment continuously or intermittently.
For example, an active agent could be delivered to the
normally-sealed environment and allowed to remain in place (i.e.,
resident) for a selected period of time (e.g., several hours)
followed by delivery of a second active agent, or delivery of a
combination of active agents. The initial active agent could be
removed before delivery of the second agent or it could be allowed
to remain in place. Alternatively, the normally-sealed environment
could be rinsed (e.g., using air, saline or another flushing
solution) before delivery of a second agent.
[0072] In some embodiments, a closure element may be attached to
the exterior surface of the medical dressing over the valve, such
that the valve is sealed shut by the closure element until the
closure element is removed or otherwise opened. For the purposes of
this disclosure the closure element is not included when
considering the dead volume of the valve. The closure element can
serve to help seal the valve or to protect it from becoming soiled.
The closure element preferably is easy to disinfect with common
disinfectants such as ethanol/water, isopropanol/water,
n-propanol/water, hydrogen peroxide, iodine or other antiseptic
composition. Most preferred closure elements prevent these
antiseptic cleaning solutions from entering the valve where they
could be forced into the wound space.
[0073] The closure element may be attached using adhesives, heat
sealing, welding, or casting, although it may be preferred that the
closure element be attached using a pressure sensitive adhesive
such that the closure element can be reattached to the medical
dressing after it is removed from its location over the valve. In
such an embodiment, the closure element may potentially be
reattached to the medical dressing over the valve to reseal the
valve and/or the closure element may be attached elsewhere on the
medical dressing to seal an opening made through the backing (e.g.,
deliver materials into the normally-sealed environment as described
herein).
[0074] The medicaments may be supplied sterile in addition to or in
place of the filter elements described. Suitable sterilization
methods include filter sterilization, ionizing radiation (e.g.,
gamma radiation, electron beam, or heat).
[0075] As mentioned previously, the medical dressing of the present
disclosure may be useful as a topical or transdermal drug delivery
device. In this embodiment the medical dressing is applied over the
treatment site and the medicament is administered through the valve
as previously described. Medicament administration can be performed
one, two, three, or many times. The medicament may be administered
as often as necessary without the need to remove the dressing.
Dressing removal can cause significant skin stripping and
irritation so a refillable rather than replaceable dressing can be
particularly advantageous for the patient.
Backings:
[0076] The medical dressings of the present disclosure are useful
in connection with any conformable backing that provides a
sufficiently impermeable barrier to the passage of liquids and at
least some gases. Representative backings may include polymeric
films and other familiar backing materials. The preferred backing
materials may be translucent or transparent polymeric films.
[0077] The backings used in connection with the present disclosure
may be high moisture vapor permeable film backings. Issued U.S.
Pat. Nos. 3,645,835 and 4,595,001 describe methods of making such
films and methods for testing their permeability. The film (and any
adhesive used thereon as described herein) may transmit moisture
vapor at a rate equal to or greater than human skin. In some
embodiments, the adhesive-coated film may transmit moisture vapor
at a rate of at least 300 g/m.sup.2/24 hrs/37.degree. C./100-10%
RH, more preferably at least 700 g/m.sup.2/24 hrs/37.degree.
C./100-10% RH, and most preferably at least 2000 g/m.sup.2/24
hrs/37.degree. C./100-10% RH using the inverted cup method as
described in U.S. Pat. No. 4,595,001.
[0078] The backings may also preferably be conformable to
anatomical surfaces. As such, when the backing is applied to an
anatomical surface, it conforms to the surface even when the
surface is moved. The backing may also be conformable to animal
anatomical joints. When the joint is flexed and then returned to
its unflexed position, the backing may stretch to accommodate the
flexion of the joint, but is resilient enough to continue to
conform to the joint when the joint is returned to its unflexed
condition. A description of this characteristic of backings can be
found in issued U.S. Pat. Nos. 5,088,483 and 5,160,315. The
backings should be sufficiently conformable to form a
circumferential seal around the treatment area such as a wound.
Examples of some potentially suitable backings may include
elastomeric polyurethane, polyester, or polyether block amide
films. These films combine the desirable properties of resiliency,
high moisture vapor permeability, and transparency.
[0079] Commercially available examples of potentially suitable
backing materials may include the thin polymeric film backings sold
under the tradenames TEGADERM (3M Company), BIOSITE (Johnson &
Johnson Company), OPSITE (Smith & Nephew). Many other backings
may also be used, including those commonly used in the manufacture
of surgical incise drapes (e.g., incise drapes manufactured by 3M
Company under the tradename STERIDRAPE and IOBAN).
[0080] Because fluids may be actively removed from the
normally-sealed environments defined by the medical dressings of
the present disclosure, a relatively high moisture vapor permeable
backing may not be required. As a result, some other potentially
useful backing materials may include metallocene polyolefins and
SBS and SIS block copolymer (e.g., KRATON type) materials could be
used.
[0081] Regardless, however, it may be preferred that the backings
be kept relatively thin (e.g., to improve conformability). For
example, it may be preferred that the backings be formed of (e.g.,
consist essentially of) polymeric films with a thickness of 200
micrometers or less, or 100 micrometers or less, potentially 50
micrometers or less, or even 25 micrometers or less.
Pressure Sensitive Adhesives:
[0082] The pressure sensitive adhesives that may preferably be used
in the medical dressings of the present disclosure may include
adhesives that are typically applied to the skin such as the
acrylate copolymers described in U.S. Pat. No. RE 24,906,
particularly a 96:4 iso-octyl acrylate:acrylamide copolymer.
Another example may include a 70:15:15 isooctyl
acrylate:ethyleneoxide acrylate:acrylic acid terpolymer, as
described in U.S. Pat. No. 4,737,410 (Example 31). Other
potentially useful adhesives are described in U.S. Pat. Nos.
3,389,827; 4,112,213; 4,310,509; and 4,323,557. Inclusion of
medicaments or antimicrobial agents in the adhesive is also
contemplated, as described in U.S. Pat. Nos. 4,310,509 and
4,323,557.
[0083] The pressure sensitive adhesives may, in some embodiments,
transmit moisture vapor at a rate greater to or equal to that of
human skin. While such a characteristic can be achieved through the
selection of an appropriate adhesive, it is also contemplated in
the present disclosure that other methods of achieving a high
relative rate of moisture vapor transmission may be used, such as
pattern coating the adhesive on the backing, as described in U.S.
Pat. No. 4,595,001. Other potentially suitable pressure sensitive
adhesives may include blown-micro-fiber (BMF) adhesives such as,
for example, those described in U.S. Pat. No. 6,994,904. The
pressure sensitive adhesive used in the medical dressing may also
include one or more areas in which the adhesive itself includes
structures such as the microreplicated structures described in U.S.
Pat. No. 6,893,655. Also useful are silicone based pressure
sensitive adhesives such as those described in International (PCT)
Published Patent Application No. U.S. 2009/062603, titled GENTLE TO
SKIN ADHESIVE, and U.S. Provisional Patent Application Ser. No.
61/522,485, filed on Aug. 11, 2011 and titled NONWOVEN WEBS AND
MULTI-COMPONENT FIBERS COMPRISING A POLYDIORGANOSILOXANE POLYAMIDE
AND METHODS OF MELT BLOWING, as well as those silicone adhesives
described in U.S. Provisional Patent Application Ser. No.
61/524,545, filed on Aug. 17, 2011 and titled A HYDROPHOBIC
ADHESIVE WITH ABSORBENT FIBERS.
Release Liners:
[0084] Release liners may be supplied with the medical dressings of
the present disclosure to protect the pressure sensitive adhesive
used to attach the dressings to the patient and create the
normally-sealed environment. Release liners that may be suitable
for use in the medical dressing of the present disclosure can be
made of supercalendered kraft paper, glassine paper, polyethylene,
polypropylene, polyester or composites of any of these materials.
The liners are preferably coated with release agents such as
fluorochemicals or silicones. For example, U.S. Pat. No. 4,472,480
describes low surface energy perfluorochemical liners. The liners
may preferably be in the form of papers, polyolefin films,
polyolefin coated paper or polyester films coated with silicone
release materials. Examples of commercially available silicone
coated release liners are POLY SLIK.TM. silicone release on
polyolefin coated papers, FL2000.TM. silicone release on film, and
STICK-NOT.TM. silicone release on supercalendered kraft paper, all
available from Loparex Inc., (Willowbrook, Ill.); silicone coated
supercalendered kraft paper from Akrosil, (Menasha, Wis.); and
silicone release film from Huhtamaki Florchheim, (Florchheim,
Germany). Another potential liner is silicone coated (1630) low
density polyethylene available from Huhtamaki.
[0085] The selection of a specific release liner may be made in
conjunction with the selection of a pressure sensitive adhesive.
Those skilled in the art will be familiar with the processes of
testing a new adhesive against different liners or a new liner
against different adhesives to arrive at the combination of
qualities desired in a final product. The considerations pertinent
to the selection of a silicone release liner can be found in
Chapter 18 of the Handbook of Pressure Sensitive Adhesive
Technology, Van Nostrand-Reinhold, 1982, pp. 384-403. U.S. Pat. No.
4,472,480 also describes considerations pertinent to the selection
of a perfluoropolyether release liner.
Carriers/Delivery Systems:
[0086] In some instances, the backings used in the medical
dressings of the present disclosure may be so flexible and supple
such that when a release liner is removed from the backing, the
backing may tend to fold and adhere to itself, interfering with the
smooth, aseptic application of the dressing to a patient's
skin.
[0087] Various delivery systems have been proposed to address this
problem such as those disclosed in U.S. Pat. No. 4,485,809; U.S.
Pat. No. 4,600,001; and EPO Publication No. 0 051 935. Carrier-type
delivery systems such as those described in U.S. Pat. No. 6,685,682
offer an alternative delivery system for use with conformable
backings. In these embodiments the carrier is attached to the top
surface of the dressing (surface facing away from the skin). The
carrier is used to facilitate placement of the dressing once the
liner is removed. After application the carrier is removed. In the
exemplary embodiment illustrated in FIG. 9, medical dressing 900
includes backing 910, normally-closed one way valve 950 having
inlet port 956, and carrier element 945. Carrier element 945 can
facilitate placement of a medical dressing of the present
disclosure over a treatment site.
[0088] Alternative carriers and/or delivery systems may include
frames, handles, and stiffening strips, as disclosed in U.S. Pat.
Nos. 6,742,522; 5,979,450; 6,169,224; 5,088,483; 4,598,004; and D
493,230. Still another potentially suitable delivery system may be
described in U.S. Patent Application Publication No. 2007/0156075
A1. In some instances, the backings can be delivered linerless
(e.g., as described in U.S. Pat. No. 5,803,086).
[0089] Also included in the present disclosure are kits comprising
a pressurized medicament container capable of filling the treatment
dressing at least once, a treatment dressing as described herein
comprising a normally closed flow control valve and optionally
absorbent, border/carrier, rate controlling film or membrane and
various other options described herein, and a means for temporarily
connecting the pressurized medicament container to the treatment
dressing and inflating the dressing. The pressurized medicament
container may be filled to a suitable pressure as supplied to
inflate the treatment dressing. The extent of inflation must be
controlled (i.e. the inflation pressure must be limited to avoid
having the dressing lift away from the treatment site and to
prevent doing damage to a wound site). In applications over wounds
the pressure should not be too high that the dressing distends into
the wound and places pressure on the wound bed which could cut off
blood flow. If the pressure in the medicament container is higher
than the desired maximum inflation pressure the kits may optionally
include a regulator either as a part of the medicament container,
the dressing, the connection means or as a separate item in the
flow path from the pressurized medicament container to the
treatment site. The regulator serves to reduce the pressure of the
delivered medicament to a pressure that will not result in dressing
lift or wound damage. For example, the medicament container may be
pressurized to 5 psig, 10 psig, 15 psig or more but a pressure of
no more than 100 mmHg greater than atmospheric pressure is desired
in the dressing at the treatment site. The regulator reduces the
pressure delivered to 100 mmHg greater than atmospheric pressure to
avoid problems. The dressings of the present disclosure may be
provided sterile in a sealed package comprising one or more
dressings. The dressings and package may be sterilized by any
suitable method including gamma radiation, electron beam radiation,
and ethylene oxide.
[0090] In some embodiments, the medical dressing having the
normally-closed one-way flow control valve can be connected to a
fluid metering system for administration of the medicament. In some
embodiments, the fluid metering system can administer multiple
doses of the medicament on a predetermined schedule into the
medical dressing via the normally-closed one-way flow control
valve. In some further embodiments, the fluid metering system can
administer various concentrations and/or various combinations of
medicament(s) (e.g., a steroidal medicament plus an antimicrobial
medicament) on a predetermined schedule into the medical dressing
via the normally-closed one-way flow control valve. In some further
embodiments, the fluid metering system can also remove fluid from
the medical dressing through a normally-closed one way outlet
valve.
EMBODIMENTS
[0091] Item 1. A medical dressing comprising:
[0092] a backing having generally opposed first and second major
surfaces, a passage defined therethrough connecting the first and
second major surfaces, and a perimeter of the second major
surface;
[0093] adhesive disposed at least proximate to the perimeter of the
second major surface; and
[0094] a normally-closed one-way flow control valve affixed to the
backing and surrounding the passage therethrough;
[0095] wherein the normally-closed one-way flow control valve
permits fluid flow in a first direction from the first major
surface to the second major surface when in an open configuration
and restricts fluid from flowing in a second direction from the
second major surface to the first major surface when in a closed
configuration; and
[0096] wherein, if the medical dressing is applied over a treatment
site, then the medical dressing defines a normally-sealed
environment over the treatment site.
Item 2. The medical dressing of item 1, wherein a dead volume
between the normally-closed one-way flow control valve and the
backing is 10 mm.sup.3 or less. Item 3. The medical dressing of any
preceding item, wherein the normally-closed one-way flow control
valve comprises an antechamber defining an external opening, and
wherein administration of a pressurized fluid through the external
opening opens the normally-closed one-way flow control valve. Item
4. The medical dressing of any preceding item, wherein application
of a positive pressure to an exterior surface of the
normally-closed one-way flow control valve opens the
normally-closed valve such that fluid within a pressurized
medicament container can enter the normally-sealed environment.
Item 5. The medical dressing of any preceding item, wherein the
normally-closed one-way flow control valve is flexible and may be
easily folded in at least one direction between the thumb and
forefinger of a healthcare worker. Item 6. The medical dressing of
any preceding item, further comprising a closure element attached
to the first major surface of the backing and covering the
normally-closed one-way flow control valve, wherein the closure
element seals the normally-closed one-way flow control valve shut.
Item 7. The medical dressing of any preceding item, further
comprising a fitting adapted for attachment to the first major
surface of the backing over the normally-closed one-way flow
control valve. Item 8. The medical dressing of any preceding item,
further comprising a barrier element attached proximate to the
second major surface of the backing. Item 9. The medical dressing
of any preceding item, further comprising a septum element attached
to the backing. Item 10. The medical dressing of any preceding
item, wherein the normally-closed one-way flow control valve is
constructed of thin films. Item 11. The medical dressing of any
preceding item, wherein the normally-closed one-way flow control
valve is constructed to provide a flattened channel which opens
upon pressurization with a pressurized medicament. Item 12. A
medical dressing kit, the kit comprising:
[0097] a medical dressing according to any of items 1 to 5;
[0098] optionally, a closure element;
[0099] optionally, a barrier element;
[0100] optionally, wound fluid absorbent material;
[0101] optionally, a rate control film/membrane
[0102] optionally, a medicament reservoir;
[0103] optionally, a fitting adapted for attachment to the external
surface of the backing over the normally-closed one-way flow
control valve; and
[0104] optionally, one or more containers of pressurized
medicament
[0105] optionally a connection means
[0106] optionally a pressure regulator.
Item 13. A medical dressing kit according to item 12, wherein the
closure element is pre-attached to the backing. Item 14. A medical
dressing kit according to item 12, wherein the closure element is
not attached to the backing. Item 15. A medical dressing kit
according to item 12, having a closure element attached to the
first major surface of the backing over the normally-closed one-way
flow control valve, wherein the closure element seals the
normally-closed one-way flow control valve shut. Item 16. A method
of treating a wound, the method comprising:
[0107] applying a medical dressing according to any one of items 1
to 11 over a wound;
[0108] introducing a pressurized fluid medicament into the
normally-sealed environment through the valved opening in the
backing.
Item 17. A method according to item 16, wherein the fluid
medicament introduced into the normally-sealed environment
comprises a gas such that the pressure within the normally-sealed
environment is in a range of from 0.1 mmHg up to 100 mm Hg for a
period of at least one minute. Item 18. A method according to item
16, wherein the fluid medicament introduced into the
normally-sealed environment comprises an oxygen concentration in a
range from 21% up to 100%. Item 19. A method according to item 16,
wherein the fluid medicament introduced into the normally-sealed
environment comprises one of a nitric oxide, ozone, iodine or
hydrogen peroxide.
[0109] The complete disclosure of the patents, patent documents,
and publications cited herein are incorporated by reference in
their entirety as if each were individually incorporated (although
conflicts between any such disclosures and the descriptions
explicitly provided herein should be resolved in favor of this
document).
[0110] Exemplary embodiments of this invention are discussed and
reference has been made to possible variations within the scope of
this disclosure. These and other variations and modifications in
the disclosure will be apparent to those skilled in the art without
departing from the scope of the disclosure, and it should be
understood that this disclosure is not limited to the exemplary
embodiments set forth herein. Accordingly, the invention is to be
limited only by the claims provided below and equivalents
thereof.
* * * * *