U.S. patent application number 12/341832 was filed with the patent office on 2009-08-27 for auto-replenishing, wound-dressing apparatus and method.
Invention is credited to Sai Bhavaraju, Troy C. Dayton, John Howard Gordon, Jeremy Heiser, Ashok V. Joshi.
Application Number | 20090216204 12/341832 |
Document ID | / |
Family ID | 40999026 |
Filed Date | 2009-08-27 |
United States Patent
Application |
20090216204 |
Kind Code |
A1 |
Bhavaraju; Sai ; et
al. |
August 27, 2009 |
AUTO-REPLENISHING, WOUND-DRESSING APPARATUS AND METHOD
Abstract
Apparatus and methods to treat skin defects include a pump with
reservoirs for a pressurization gas and a fluid, the fluid loaded
at a factory and sealed or filled at point of use through a valve,
septum, or the like. Upon activation, the pump generates a gas
introduced into the gas reservoir, a movable wall of which
displaces a movable wall of a fluid source, thus dispensing the
fluid into the dressing to spread throughout irrespective of
orientation of the dressing, maintaining a transport fluid (e.g.
carrier) in the dressing and in contact with a skin defect being
treated. Delivery may be periodic, constant, programmatically
controlled, or manual. A dressing may maintain intimate contact, a
transport fluid, and a controllable concentration of active
ingredient against a skin defect. Apparatus and methods to
replenish a dressing with a therapeutically effective concentration
of a fluid deliver a fluid carrier containing an active ingredient.
The fluid may be stored in and delivered from a pump mechanism
including reservoirs for a pressurization gas and the fluid, which
may be loaded at a factory and sealed or filled at point of use
through a valve, septum, or the like. The dressing may have a
distribution network, and multiple members, dispensing the fluid
into a wick maintaining a transport fluid (e.g. carrier)
distributed in the dressing and in contact with a skin defect being
treated. Delivery may be periodic, constant, programmatically
controlled, or manual to maintain intimate contact, a transport
fluid, and a controllable concentration of active ingredient
against wounded tissue.
Inventors: |
Bhavaraju; Sai; (West
Jordan, UT) ; Dayton; Troy C.; (Syracuse, UT)
; Gordon; John Howard; (Salt Lake City, UT) ;
Heiser; Jeremy; (US) ; Joshi; Ashok V.; (Salt
Lake City, UT) |
Correspondence
Address: |
CERAMATEC, INC.
2425 SOUTH 900 WEST
SALT LAKE CITY
UT
84119
US
|
Family ID: |
40999026 |
Appl. No.: |
12/341832 |
Filed: |
December 22, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61015952 |
Feb 27, 2008 |
|
|
|
Current U.S.
Class: |
604/290 ;
604/305 |
Current CPC
Class: |
A61F 2013/002 20130101;
A61F 2013/00268 20130101; A61M 35/00 20130101; A61F 2013/00174
20130101; A61M 35/006 20130101; A61F 2013/0017 20130101; A61F
13/00068 20130101 |
Class at
Publication: |
604/290 ;
604/305 |
International
Class: |
A61M 35/00 20060101
A61M035/00; A61F 13/00 20060101 A61F013/00 |
Claims
1. A dressing comprising: a feed conduit for delivering a fluid to
a distribution member, the distribution member receiving and
distributing the fluid substantially uniformly across the
distribution member, irrespective of the orientation of the
distribution member.
2. The dressing of claim 1, wherein the fluid comprises an active
ingredient.
3. The dressing of claim 1, wherein an interface member is
positioned between the distribution member and a skin defect being
treated by the dressing, the interface member transporting the
fluid from the distribution member into contact with a skin
defect.
4. The dressing of claim 3, wherein the interface member comprises
at least one material chosen from a non-adhering polymer and a
bioabsorbable polymer.
5. The dressing of claim 3, wherein the interface member comprises
at least one structure chosen from a sheet, a foam, a gel, gauze, a
porous matrix, a honeycomb, a mop of fibrous material, a comminuted
fibrous material, and a tubular structure.
6. The dressing of claim 1, wherein the distribution member
maintains a predetermined amount of fluid substantially uniformly
across the distribution member and allows said distribution of
fluid to communicate with a skin defect.
7. The dressing of claim 1, wherein the distribution member
maintains a concentration of active ingredient in the fluid
substantially uniformly across the distribution member and allows
said concentration of active ingredient in the fluid to communicate
with a skin defect.
8. The dressing of claim 1, wherein the distribution member
maintains a concentration of active ingredient in the fluid
substantially uniformly within a predetermined range of
concentration across the distribution member and allows said
concentration in said range to communicate with a skin defect.
9. The dressing of claim 1, wherein the distribution member
comprises material that allows the spread of fluid substantially
uniformly across the distribution member by wicking action.
10. The dressing of claim 9, wherein the force exerted on the fluid
by the wicking action is greater than or equal to the force exerted
on the fluid by gravity.
11. The dressing of claim 9, wherein the distribution member
comprises at least one material chosen from a polymer, a woven
fabric, a non-woven fabric, a naturally occurring fiber, a sponge,
a fiber matrix, a gauze, absorbent material, adsorbent material, a
gel, and a foam.
12. The dressing of claim 1, further comprising a protective member
positioned adjacent the distribution member.
13. The dressing of claim 12, wherein the protective member is
semi-occlusive.
14. The dressing of claim 1, wherein the feed conduit is connected
to a fluid source for replenishing the fluid in the distribution
member with or without additional human intervention.
15. The dressing of claim 14, wherein the fluid source controls a
fluid flow to the distribution member.
16. The dressing of claim 1, comprising one or more members
structured to operate as at least one of an interface member, a
distribution member, a fluid transport member, a protective member,
a tenting member, a fluid absorber, and a combination thereof.
17. The dressing of claim 1, wherein the distribution member or
dressing is configured to be cut to a desired size and still
maintain a substantially uniform volume of fluid across the
distribution member.
18. The dressing of claim 1, wherein the distribution member
comprises distribution tubes for distributing a volume of fluid
substantially uniformly across the distribution member.
19. The dressing of claim 1, wherein the distribution member
comprises a porous pouch.
20. A dressing comprising: a feed conduit for delivering a fluid to
a distribution member, the distribution member receiving and
distributing the fluid substantially uniformly across the
distribution member, irrespective of the orientation of the
distribution member; wherein the distribution member comprises
material that allows the spread of fluid substantially uniformly
across the distribution member by wicking action; and wherein the
distribution member is configured to be cut to a desired size and
still maintain a substantially uniform volume of fluid across the
distribution member.
21. A dressing comprising: a distribution member; a feed conduit
for delivering a fluid to the distribution member, the distribution
member configured to receive and distribute the fluid substantially
uniformly across the distribution member by wicking action,
irrespective of the orientation of the distribution member; and an
interface member is positioned between the distribution member and
a skin defect being treated by the dressing, the interface member
transporting the fluid into contact with the skin defect.
22. The dressing of claim 21, wherein the distribution member
maintains a predetermined amount of fluid substantially uniformly
across the distribution member.
23. The dressing of claim 22, wherein the distribution member
maintains a concentration of active ingredient in the fluid
substantially uniformly across the distribution member and allows
said concentration of active ingredient in the fluid to communicate
with the skin defect.
24. The dressing of claim 23, wherein the distribution member
maintains a concentration of active ingredient in the fluid
substantially uniformly within a predetermined range of
concentration across the distribution member and allows said
concentration in said range to communicate with the skin
defect.
25. The dressing of claim 21, further comprising a protective
member positioned adjacent the distribution member.
26. The dressing of claim 25, wherein the protective member is
semi-occlusive.
27. The dressing of claim 25, comprising one or more members
structured to operate as at least one of the interface member, the
distribution member, and the protective member, a fluid transport
member, a tenting member, a fluid absorber, and a combination
thereof.
28. The dressing of claim 21, wherein the distribution member is
configured to be cut to a desired size and still maintain a
substantially uniform volume of fluid across the distribution
member.
29. A dressing comprising: a distribution member comprising at
least one material chosen from a polymer, a woven fabric, a
non-woven fabric, a naturally occurring fiber, a sponge, a fiber
matrix, a gauze, absorbent material, adsorbent material, a gel, and
a foam; a feed conduit for delivering a fluid to the distribution
member, the distribution member configured to receive and
distribute the fluid substantially uniformly across the
distribution member by wicking action, wherein the force exerted on
the fluid by the wicking action is greater than the force exerted
on the fluid by gravity, and wherein the distribution member is
configured to maintain a predetermined amount of fluid
substantially uniformly across the distribution member, wherein the
fluid is received, distributed, and maintained irrespective of the
orientation of the distribution member; an interface member is
positioned between the distribution member and a skin defect being
treated by the dressing, the interface member transporting the
fluid into contact with the skin defect, wherein the interface
member comprises at least one material chosen from a non-adhering
polymer and a bioabsorbable polymer; and a semi-occlusive
protective member positioned adjacent the distribution member.
30. The dressing of claim 29, wherein the distribution member
maintains a concentration of active ingredient in the fluid
substantially uniformly across the distribution member and allows
said concentration of active ingredient in the fluid to communicate
with the skin defect.
31. The dressing of claim 30, wherein the distribution member
maintains a concentration of active ingredient in the fluid
substantially uniformly within a predetermined range of
concentration across the distribution member and allows said
concentration in said range to communicate with the skin
defect.
32. The dressing of claim 31, wherein the distribution member is
configured to be cut to a desired size and still maintain a
substantially uniform volume of fluid across the distribution
member
33. The dressing of claim 32, comprising one or more members
structured to operate as at least one of the interface member, the
distribution member, the protective member, a fluid transport
member, a tenting member, a fluid absorber, and a combination
thereof.
34. A method for treating a skin defect, the method comprising:
providing a dressing comprising: a feed conduit; and a distribution
member in fluid communication with the feed conduit, the
distribution member configured to receive a fluid and comprising a
material to substantially uniformly distribute the fluid across the
distribution member irrespective of the orientation of the
distribution member; applying the dressing to a skin defect;
supplying a fluid to the distribution member through the feed
conduit; and distributing the fluid substantially uniformly across
the distribution member.
35. The method of claim 34, wherein the fluid comprises an active
ingredient.
36. The method of claim 34, wherein an interface member is
positioned between the distribution member and the skin defect
being treated by the dressing, the interface member transporting
the fluid into contact with the skin defect.
37. The method of claim 34, wherein the distribution member
maintains a predetermined amount of fluid substantially uniformly
across the distribution member.
38. The method of claim 35, wherein the distribution member
maintains a concentration of active ingredient in the fluid
substantially uniformly across the distribution member and allows
said concentration of active ingredient in the fluid to communicate
with the skin defect.
39. The method of claim 35, wherein the distribution member
maintains a concentration of active ingredient in the fluid
substantially uniformly within a predetermined range of
concentration across the distribution member and allows said
concentration in said range to communicate with the skin
defect.
40. The method of claim 34, wherein the distribution member
comprises material that allows the spread of fluid substantially
uniformly across the distribution member by wicking action.
41. The method of claim 40, where the force exerted on the fluid by
the wicking action is greater than or equal to the force exerted on
the fluid by gravity.
42. The method of claim 34, further comprising a protective member
positioned adjacent the distribution member.
43. The method of claim 34, wherein the distribution member
comprises distribution tubes for distributing a volume of fluid
substantially uniformly across the distribution member.
44. The method of claim 34, wherein the distribution member
comprises a porous pouch.
45. The method of claim 34, wherein supplying a fluid comprises
supplying a pre-determined quantity of fluid containing an active
ingredient.
46. The method of claim 34, further comprising priming the dressing
with a quantity of fluid.
47. The method of claim 34, further comprising providing a bolus of
fluid to the dressing.
48. The method of claim 34, further comprising manually providing
fluid from a fluid source to the dressing.
49. The method of claim 34, further comprising automatically
providing fluid from a fluid source to the dressing.
50. The method of claim 34, wherein the dressing further comprises
a controller, and wherein supplying the fluid to the distribution
member comprises programming the controller to supply the fluid at
a predetermined flow rate or time interval.
51. The method of claim 34, further comprises substantially
uniformly distributing the fluid to the skin defect from the
distribution member.
52. The method of claim 35, wherein supplying fluid to the
distribution member comprises maintaining a fluid with a
concentration of active ingredient greater than a predetermined
threshold over a predetermined period of time.
53. The method of claim 35, wherein supplying fluid to the
distribution member comprises maintaining a fluid with a
concentration of active ingredient lesser than a predetermined
threshold over a predetermined period of time.
54. The method of claim 35, wherein the active ingredient comprises
at least one composition chosen from an antimicrobial, an
antibiotic, an antifungal, an antiviral, an antiseptic, and an
antibacterial agent.
55. The method of claim 35, wherein the active ingredient comprises
at least one composition chosen from an analgesic, a palliative,
and an anti-inflammatory agent.
56. The method of claim 35, wherein the active ingredient comprises
at least one composition chosen from de-ionized water, a polymeric
gel, a saline composition, and a hydrocolloid.
57. The method of claim 35, wherein the active ingredient comprises
at least one beneficial agent chosen from an enzymatic debrider, a
tissue growth factor, a scar-reducing agent, tissue cells, topical
nutrients, a coagulant, nitric oxide, oxygen gas, ozone, and a gene
therapy agent.
58. The method of claim 35, wherein the active ingredient is
selected to be therapeutically effective in treating a
dermatological disorder chosen from a skin defect, an allergy
eruption, a skin cancer, a rash, a burn, a growth, a cyst, a wart,
a tumor, an ulcer, a boil, an incision, a graft, oiliness, dryness,
wrinkles, blemishes, discolorations, and trauma.
59. The method of claim 34, further comprising trimming the
dressing to a desired shape corresponding to a treatment area.
60. A method for treating a skin defect, the method comprising:
providing a dressing comprising: a feed conduit; and a distribution
member in fluid communication with the feed conduit, the
distribution member configured to receive a fluid and comprising a
material to substantially uniformly distribute the fluid across the
distribution member irrespective of the orientation of the
distribution member; cutting the dressing to a desired shape;
applying the dressing to a skin defect; supplying a fluid having an
active ingredient to the distribution member through the feed
conduit; distributing the fluid substantially uniformly across the
distribution member; and distributing the fluid substantially
uniformly to a skin defect irrespective of the orientation the
distribution member.
61. The method of claim 60, further comprising priming the dressing
with a quantity of fluid.
62. The method of claim 60, further comprising providing a bolus of
fluid to the dressing.
63. The method of claim 60, further comprising automatically
controlling the supply of fluid to the distribution member.
64. The method of claim 63, wherein controlling the supply of fluid
comprises programming a controller to supply the fluid at a
predetermined flow rate or time interval.
65. The method of claim 64, wherein supplying fluid to the
distribution member comprises maintaining a fluid with a
concentration of active ingredient greater than a predetermined
threshold over a predetermined period of time.
66. The method of claim 65, wherein supplying fluid to the
distribution member comprises maintaining a fluid with a
concentration of active ingredient lesser than a predetermined
threshold over a predetermined period of time.
67. The method of claim 60, comprising one or more members
structured to operate as at least one of an interface member, a
distribution member, and a protective member.
68. A fluid delivery system comprising: a housing having, an
interior volume, inextensible and vented to discharge gas
therefrom, and containing reservoir and a fluid source in contact
with one another; a fluid source containing a fluid having a first
wall flexible to move in response to substantially any pressure and
substantially impervious to the fluid, and an outlet to dispense
the fluid; a reservoir comprising a second wall, in contact with
the first wall to move therewith, substantially impervious to a
gas; a galvanic cell in communication with the reservoir and
comprising chemicals selected to produce a gas within the
reservoir; a dressing to expose the fluid to a skin defect of a
subject, said dressing comprising a distribution member configured
to receive the fluid and comprising a material to substantially
uniformly distribute the fluid across the distribution member by
wicking action irrespective of the orientation of the distribution
member; and a conduit connectable to the outlet and in fluid
communication with the distribution member to replenish the fluid
in the distribution member.
69. The fluid delivery system of claim 68, wherein the fluid
comprises an active ingredient.
70. The fluid delivery system of claim 68, wherein the dressing
further comprises a protective member positioned adjacent the
distribution member.
71. The fluid delivery system of claim 70, wherein the protective
member is semi-occlusive.
72. The fluid delivery system of claim 68, wherein an interface
member is positioned between the distribution member and a skin
defect being treated by the dressing, the interface member
transporting the fluid into contact with the skin defect.
73. The fluid delivery system of claim 68, wherein the distribution
member comprises material that allows the spread of fluid
substantially uniformly across the distribution member by wicking
action.
74. The fluid delivery system of claim 73, wherein the force
exerted on the fluid by the wicking action is greater than or equal
to the force exerted on the fluid by gravity.
75. The fluid delivery system of claim 68, wherein the distribution
member comprises distribution tubes for distributing a volume of
fluid substantially uniformly across the distribution member.
76. The fluid delivery system of claim 68, wherein the distribution
member comprises a porous pouch.
77. The fluid delivery system of claim 68, wherein the distribution
member maintains a substantially uniform fluid volume across the
distribution member and allows the fluid to communicate with the
skin defect upon reaching or exceeding a predetermined saturation
level.
78. The dressing of claim 68, wherein the distribution member
maintains a concentration of active ingredient in the fluid
substantially uniformly across the distribution member and allows
said concentration of active ingredient in the fluid to communicate
with the skin defect.
79. The dressing of claim 68, wherein the distribution member
maintains a concentration of active ingredient in the fluid
substantially uniformly within a predetermined range of
concentration across the distribution member and allows said
concentration in said range to communicate with the skin
defect.
80. The fluid delivery system of claim 68, wherein the fluid source
outlet comprises a regulator to maintain pressure in the fluid
source greater than the ambient pressure to minimize operational
variations due to variations in at least one of the ambient
temperature, the barometric pressure, or the orientation of the
device.
81. The fluid delivery system of claim 68, further comprising a
controller connected to the galvanic cell in a circuit to control
the generation of the gas in the reservoir, thereby controlling a
delivery rate of the fluid from the fluid source.
82. The fluid delivery system of claim 81, wherein the controller
comprises a fixed or variable resistor and a switch.
83. The fluid delivery system of claim 81, wherein at least a
portion of the controller is located separately from the galvanic
cell and is in communication with the cell by at least one of
mechanical hardware, electromagnetic, radio frequency, magnetic, or
optical feedback or circuit.
84. The fluid delivery system of claim 81, wherein the controller
is located inside the reservoir.
85. The fluid delivery system of claim 81, wherein the controller
further comprises a processor programmatically controlling the
value of resistance in the circuit.
86. The fluid delivery system of claim 85, further comprising a
fill port in fluid communication with the fluid source.
87. The fluid delivery system of claim 86, wherein the fill port
comprises a septum through which a syringe may penetrate to access
the fluid source.
88. The fluid delivery system of claim 68, further comprising a
sensor operably connected to provide inputs to the processor to
control the value of resistance in accordance with an algorithm
therewith.
Description
RELATED APPLICATIONS
[0001] This application is related to and claims the benefit of
U.S. Provisional Patent Application Ser. No. 61/015,952 entitled
"AUTO-REPLENISHING, WOUND-DRESSING APPARATUS AND METHOD" and filed
on Feb. 27, 2008 for Sai Bhavarju et al., which is incorporated
herein by reference.
BACKGROUND
[0002] 1. The Field of the Invention
[0003] This invention relates to treatment of skin defects, and in
particular to control and delivery of treatment substances to a
dressing on a skin defect.
[0004] 2. The Background Art
[0005] Skin defects may be inflicted by people, machines, tools,
vehicles, animals, plants, the environment, and many other factors.
Likewise, pressure, ailments, infections, and disease may create
sores, open wounds, and other skin defects. Skin defects may be
treated by a variety of physical processes, materials, conditions,
controls, and the like, each based on a particular theory,
experiment, regimen, or other basis of justification. Meanwhile,
skin defects may be characterized by their significance or
seriousness, as well as their nature, their susceptibility to
treatment, or the like. Skin defects maybe defined as wounds,
incisions, or an injury to the body (as from trauma, pathology, or
surgery) that typically involves laceration or breaking of a
membrane (as the skin or mucous membrane) and usually damage to
underlying tissues. Furthermore a wounds or skin defect may be
characterized as minor, superficial, major, traumatic, acute,
chronic, fatal, or the like.
[0006] Skin defects may require isolation from an environment,
exposure to a particular environment, treatment by exposure to a
medicament, covering, uncovering, and so forth. One area of
continuing interest is the treatment of skin defects by applying a
dressing. Typically, treatment may include some type of anti-sepsis
process. After application of medicament such as an antiseptic,
antibiotic, or the like in tincture or ointment form, a bandage or
other covering may be applied to control or limit access to the
skin defects by environmental agents (e.g. air, dirt, touching,
etc.).
[0007] In treating skin defects, applying a medicament may only
solve part of the problem. Changing a dressing, replenishing a
quantity or concentration of a medicament, controlling the access,
contact, and concentration of an active ingredient applied to skin
defects, and verification of the foregoing are typically difficult
to do. Application of a constant or even reliable or consistent
concentration of a medicament is difficult to accomplish, even for
a regularly attended patient.
[0008] For example, application of a salve, ointment, cream,
irrigation, tincture, or the like occurs at a point in time. The
dressing itself may soak up the medicament fluid, removing the
contact with the skin defects. Drying of a carrier portion of a
medicament fluid may inhibit chemical activity of an active
ingredient by removing the necessary transport fluid required for
migration, diffusion, or the like. Drying of tissues, blood, or
serum may inhibit the action or effectiveness of an active
ingredient, and may even block access by an active ingredient to
underlying skin defect. Thus, finding a proper delivery mechanism
to consistently, regularly, or constantly apply the right amount of
a therapeutically effective active ingredient may be problematic in
many instances.
[0009] Once a medicament fluid is applied as a salve, liquid,
tincture, aspersion, cream, irrigation, or the like, the problem of
the concentration of the active ingredient may actually render the
application ineffective relatively quickly. Many medicaments, once
applied, have a rapidly decaying, uncontrolled, or ineffective
concentration. Subsequently the concentration of an active
ingredient in the bulk of a medicament fluid is necessarily much
higher than the concentration migrating to the affected skin defect
area. Thus the delivered concentration may become inappropriate.
Some dressings e.g. impregnated dressings deliver either below the
therapeutic range or above it causing inadequate treatment or side
effects and in the case of antibiotics possible resistance.
[0010] Accordingly, what is needed is a method and system for
consistent delivery over time of a specific volume, specific
concentration and/or therapeutically effective concentration of an
active ingredient of a beneficial fluid to the site of skin defect.
Also desirable would be supplying a specific volume, specific
concentration and/or therapeutically effective concentration of a
fresh active ingredient in a programmable manner to be within the
therapeutic window to eliminate effects due to under delivery or
over delivery. Also desirable is a method for maintaining a
transport fluid (e.g. carrier, moisture, tissue moisture, etc.)
available to support delivery of the active ingredient to the skin
defect. It would be an advance in the art to provide a system and
method to maintain a prescribed transport path, and effective
concentration of fresh active ingredient to the site of the skin
defect.
BRIEF SUMMARY OF THE INVENTION
[0011] In accordance with the foregoing, an apparatus and method in
accordance with the invention may include a fluid delivery system
that includes a housing with reservoirs for a pressurization gas
and sources for a medicament fluid. The fluid may be loaded into a
reservoir at a factory and sealed, or may be filled at the point of
use through a valve, septum, or the like. Filling the device at the
point of use includes the ability to select from fluids containing
a variety of appropriate fresh actives or combinations thereof.
Point of use or in situ filling has the added advantage of
separating the shelf life and handling requirements of the device
from the self life and handling requirements of the active. This
may also be referred to as In situ filling.
[0012] The system of fluid delivery may include a housing having an
inextensible interior volume to contain reservoirs and fluid
sources in contact with one another. A fluid source may have a wall
flexible or otherwise able to move in response to pressure, being
sealed to contain and maintain a fluid comprising an active
ingredient disposed in a fluid carrier. An inlet port, such as a
septum may provide sterile access to the fluid source to introduce
the fluid. An outlet port is provided for the fluid source to
dispense the fluid.
[0013] A reservoir containing a gas moves at least one wall in
response to pressure from gas output of a galvanic cell within or
outside, but in communication with the reservoir. An electric
circuit may control current flow to control the rate of generation
of gas. The circuit may use a resistor and switch, a more
sophisticated control circuit, or a microprocessor controller to
control current and thus the gas generation rate. The electrical
circuit may be within the reservoir or within the housing or
outside the housing. The electrical circuit may be controlled
remotely or directly, by electrical, electromagnetic, magnetic,
optical or mechanical means.
[0014] An outlet dispenses the fluid from the fluid source in
response to displacement of its wall by the gas reservoir, sending
the fluid through a feed conduit to a dressing. The term conduit,
feed conduit, feed line, and tubing may be used interchangeably
throughout this disclosure. The feed conduit may be as short or as
long as desired, supporting placement of the pump nearby, or remote
from, the dressing. The feed conduit may include a restricted tube
providing resistance to the fluid flow, thereby establishing back
pressure within the fluid source. By selection of appropriate
tubing and flow rate, a certain value of back pressure can be
established within the fluid source.
[0015] Upon activation, the fluid delivery system may generate a
gas into the gas reservoir having a movable wall. The movable wall
of the gas reservoir exerts pressure and displacement against a
movable wall of the fluid source or reservoir, thus displacing the
fluid. It will be appreciated by those of skill in the art that the
combination of the housing, gas reservoir, and fluid source may be
configured as a pump or pump mechanism. The displaced fluid may
pass through a feed conduit to a dressing and ultimately to a skin
defect to which the dressing is applied.
[0016] The dressing may include a distribution member which may be
a wicking layer, a manifold of tubes with apertures, or a pouch
with pores that allows the fluid to be distributed substantially
uniformly irrespective of orientation of the dressing. In one
embodiment, the distribution member maintains a fluid in the
dressing and in contact with the skin defect being treated. The
fluid may be a transport fluid or carrier for conveying an active
ingredient to the skin defect.
[0017] A connector positioned on the dressing connects the feed
conduit to a distribution member portion of the dressing. The
connector may be advantageously positioned centrally on the
dressing even though it may be anywhere on the dressing. The
distribution member may distribute the fluid there across,
maintaining substantially even wetting across the domain
irrespective of orientation of the dressing. The fluid may saturate
the wicking portion, thus making the fluid available to be in
intimate contact with the skin defect. The orientation independence
of the wicking member may be accomplished by implementing various
effects, including capillary action, hydrophobic/hydrophilic nature
of the layer, surface tension optimization, composition, or texture
and weave patterning of the layer, or the effects of evaporation.
These effects individually or in combination are referred to
"wicking action."
[0018] When the distribution member is a manifold, the fluid may
exit the feed conduit and into a manifold and exit substantially
evenly through the apertures irrespective of orientation by
maintaining a high fluid pressure in the manifold relative to
barometric pressure. The fluid may also be delivered substantially
evenly through the pores in the pouch due to the comparatively high
and uniform pressure across the plenum created by the pouch. A
specific volume, specific concentration and/or therapeutically
effective concentration, or in other words a predetermined range of
concentration, of the active ingredient may thus be available and
in intimate contact with the skin defect, providing a transport
fluid, active ingredient, constant rate, controllable and renewable
concentration, and intimate contact. The terms manifold, header,
arms, distribution tubes, tree structure, and plenum are used
interchangeably throughout this specification.
[0019] The dressing may function effectively with any generic
source other than the specific pump system described herein.
Therefore, the source may be manual, such as a syringe, or any
other delivery mechanism including gravity feed, mechanical pumping
etc. The source can supply fluid continuously, discontinuously,
programmably, manually, or the like.
[0020] In one embodiment, the dressing is configured to be cut to
size, and still maintain the functional properties of the dressing.
This will allow the dressing to be adaptable to the size of the
skin defect.
[0021] The fluid may be configured as a liquid having an active
ingredient dissolved within the liquid, or suspending as a
micro-pulverized particulate, all disposed within a liquid having a
viscosity selected to optimize a therapeutic effect a fluid may
have a viscosity ranging from a very thick, honey-like substance,
to a comparatively aqueous like, such as water or other liquid
base. Furthermore, a fresh active is a quality of material that
remains substantially in its original state and has not been
degraded. A fresh active may also be provided in quantities that
need not anticipate such degradation or change in the kinetics of
delivery. For the purposes of this disclosure the terms fluid,
fresh active, and medicament may be used in similar manners
discernable by one schooled in the art. A medicament maybe a fluid
or it may be in some other form.
[0022] The active ingredient may be an agent having antimicrobial,
antibiotic, analgesic, anti-inflammatory, hydrating, growth
promotion, enzymatic debridement, antiseptic, irrigation,
anesthetic, or emollient effect, and may be systemic, penetrating,
or topical. The fluid carrier of the fluid may be a liquid, gas,
gel, sol, thixotropic, colloid, or other fluid, and may carry the
active ingredient dissolved therein or suspended as particles in
suspension.
[0023] The housing may be substantially rigid and made of metal,
metal alloy, polymer, reinforced polymer, ceramic, or the like.
Steel, stainless, brass, bronze, aluminum, titanium, and copper as
well as olefinic, styrenic, polycarbonate, and elastomeric
hydrocarbons may serve adequately. The housing may be transparent
to visible light, which may provide sight monitoring, but opacity
may provide protection of the integrity of the fluid. The housing
may not be gas tight, but vented, thus allowing point of use
filling of the fluid source or other actions expelling gas from the
housing during operation.
[0024] Any reservoir or fluid source may have a pressure-relief
mechanism, such as a vent or check valve, to regulate pressure,
resist backflow, prevent rupture, or the like. The fluid source may
be filled by a syringe, through a valve or septum, and may be
overfilled in order to prime the feed conduit, the dressing, or
both prior to activation of the gas generator. Reservoirs or fluid
sources may be permanent or replaceable, single use or refillable,
or the like. Likewise, the housing may be disposable or reusable,
sealed, or openable. The gas present in the reservoir may be vented
at any time. The fluid source may be pre-filled or filled at the
point of use, and disposable or refillable. The point of use
capability allows the user to select the suitable treatment among
many options and greatly extends shelf life.
[0025] Gases from the gas generator may be any of those readily
generated by electrochemical means. For example hydrogen, oxygen,
nitrogen, or carbon dioxide may be generated by galvanic cells
without any need for external power. Typically, for a gas phase
device with higher operating pressure comes less sensitivity to the
environment, particularly the effects of changes in ambient
temperature and pressure are proportionately lessened with higher
operating pressures. Greater than ambient operating pressure
substantially improves the precision and accuracy of the device
performance. Significantly higher operating pressures reduce the
ambient effects substantially.
[0026] The gas generator may include a galvanic cell completely
contained within the gas reservoir. The gas reservoir may be formed
of a dielectric material to further insulate the electric circuit
inside. The circuit may be outside the reservoir or even outside
the housing, but sealing may be easier if no penetrations are
required in the wall or seams or the reservoir. Actuation may be
direct or remote, from a mechanical force, magnetic field, electric
pulse, radio frequency signal, acoustic wave, or the like. Any
activity of the apparatus may be indicated by an indicator
identifying an "on" condition.
[0027] The feed conduit may be formed to be substantially
inextensible, or may respond to pressure by including a pressure
accumulator or simply an elastic portion to expand to ameliorate
any sudden increase in pressure
[0028] In use, an apparatus having a housing and a flexible
reservoir and fluid source may have a selected fluid introduced as
a fluid, and may be filled in a manner to prime the feed conduit,
dressing, or both by injecting the fluid into the fluid source.
Filling may pressurize the fluid source and force open a check
valve, filling the feed conduit, and partially filling or
saturating the dressing. Filling may also result in the initial
pressurizing of the fluid source, expediting the need for the gas
bag to do so and decreasing start up time.
[0029] The distribution member may be a manifold that distributes
the fluid to various regions of the wick portion thereof. Tubes
having perforations or orifices to resist flow may maintain a
substantially equal pressure inside the distribution manifold.
Sizes of path lengths, diameters, orifices, or the like may control
pressure among outlets of tubes, plenums, pouches, bags, or the
like to effect even distribution of the fluid.
[0030] A multi-member dressing may include a distribution member
that may be a wicking layer receiving the fluid, a protective
member that may or may not be configured to protect the dressing
from the environment and provide for vapor transmission, a transfer
or transport member to transfer the fluid to the wicking layer, a
fluid absorber to absorb excessive fluid being delivered or for
absorbing the wound exudate, a tenting member positioned at the rim
of the dressing to provide for lateral evaporation, and an
interface member between the wicking layer and the treated skin
defect to transfer the fluid thereto from the wicking layer while
performing any other function needed, such as anti-adhesion, or the
like. Alternatively, the dressing may comprise at least one
functional member consisting of a distribution member, and
additionally an interface member, transport member, barrier member,
fluid absorber, any of said members could be integrated to achieve
multiple functions in one or more members.
[0031] An interface member may be formed as a sheet, foam, gel,
gauze, porous matrix, honeycomb, mop of fibrous material,
comminuted fibrous material, nanotube composite structure, or the
like, or any combination thereof. The material thereof may be a
biodegradable copolymer, dermal regeneration template,
bioabsorbable gel, anti-adhesion polymer, skin substitute,
moisture-retaining natural or synthetic composition, angiogenic
composition, antimicrobial composition, or the like, or any
combination thereof. The carrier along with the active ingredient
may be delivered directly to the skin defect. Alternatively the
active alone may be transferred to the skin defect by diffusion or
migration. The current device allows maintenance of fluid balance
in the skin defect under treatment. For example, moisture may be
provided to the skin defect and excess moisture may be removed by
vapor transmission or by an absorptive member. The interface layer
may also be referred to as the non adhering layer.
[0032] The distribution member material may be a polymer sheet,
woven fabric, non-woven fabric, naturally occurring fiber, sponge,
fiber matrix, gauze, absorbent material, adsorbent material, gel,
foam, or the like, or any combination thereof. Systems and methods
in accordance with the foregoing may treat dermatological
disorders, incisions or deeper wounds. For example embodiments of
systems and methods in accordance with the invention may be useful
for delivering a fluid prescribed for a cut, laceration, scrape,
allergy eruption, skin cancer, rash, burn, undesirable growth,
cyst, wart, tumor, ulcer, boil, irritation, incision, trauma or the
like.
[0033] In general, a therapeutically effective concentration of an
active ingredient may be delivered to the site of a disorder and
delivered by intimate contact through the dressing. A pore size in
a wicking portion of a dressing may be selected evenly distribute
the fluid carrier containing the active ingredient, independent
from orientation.
[0034] The described apparatus for delivering fresh fluids to the
skin defects may also be coupled with other well known wound
treatments such as debridement, negative pressure wound therapy,
phototherapy, surgical treatments, compression therapy, tissue
replacement or the like.
[0035] All the components in the described dressing have
configurations that function independently from their orientation.
Thus, the dressing or system as a whole may operate independent of
orientation constraints.
[0036] The system is storage stable. Due to the stability of the
mechanical and chemical systems, and the empty or closed nature of
the mechanical systems, all may be stored for an extended period of
time (e.g. months or years) before being put to use by point of use
filling of the fluid source.
[0037] Whether delivered at a substantially constant rate, periodic
dosage volume, feedback controlled saturation or moisture content,
chemically detectable concentration, or by manual intervention,
delivery of a pre-selected, therapeutically effective, threshold
concentration may be prescribed. The rate may be at a threshold
value or in a range. The control points for either a threshold
value or a range may be selected, and the fluid delivered to
effectively control pain, biotic growth, hydration, aeration,
chemical reactions, biological process, or the like, or any
suitable combination thereof.
[0038] Thus a periodically, constantly, or programmatically
delivered amount of a fluid into a dressing may maintain intimate
contact, a transport fluid, and a controllable concentration of
fresh active ingredient to a site of skin defect. The term skin
defect could be any dermatological disorder such as a wound,
allergy eruption, skin cancer, rash, burn, undesirable growth,
cyst, wart, tumor, ulcer, boil, irritation, incision, graft,
oiliness, dryness, wrinkles, blemishes, discolorations, and trauma.
The term "skin defect" may be used interchangeably with any of
these terms throughout the specification, depending upon the
context in which the term is used.
BRIEF DESCRIPTION OF THE DRAWINGS
[0039] The foregoing features of the present invention will become
more fully apparent from the following description and appended
claims, taken in conjunction with the accompanying drawings.
Understanding that these drawings depict only typical embodiments
of the invention and are, therefore, not to be considered limiting
of its scope, the invention will be described with additional
specificity and detail through use of the accompanying drawings in
which:
[0040] FIG. 1 is a perspective view of one embodiment of a fluid
delivery system for delivery of a fluid to a dressing for a skin
defect;
[0041] FIG. 2 is a perspective view of various alternative
embodiments of a pump configured for use in a fluid delivery system
and method in accordance with the invention;
[0042] FIG. 3 is a perspective view of various alternative
embodiments of feed conduits for conducting a fluid from a pump in
accordance with the invention;
[0043] FIG. 4 is a perspective view of various configurations of a
dressing for use in a fluid delivery system and method in
accordance with the invention;
[0044] FIG. 5 is a perspective view of various embodiments of
distribution systems within a dressing in accordance with the
invention;
[0045] FIG. 6 is a perspective view of one embodiment of a dressing
in various orientations that may be occupied during service in
accordance with the invention;
[0046] FIG. 7 is a perspective view of various members that may be
consolidated to form a dressing in accordance with the
invention;
[0047] FIG. 8 is a schematic diagram of a gas generator with
various alternative embodiments on the controller therefore in
accordance with the invention;
[0048] FIG. 9 is a side plan view of a cross-section of one
embodiment of a housing and reservoir and fluid source system for a
pump in accordance with the invention; and
[0049] FIG. 10 is a perspective cutaway view of an alternative
embodiment of a housing and enclosed reservoir and fluid source in
accordance with the invention.
DETAILED PREFERRED EMBODIMENTS DESCRIPTION
[0050] It will be readily understood that the components of the
present invention, as generally described and illustrated in the
drawings herein, could be arranged and designed in a wide variety
of different configurations. Thus, the following more detailed
description of the particular embodiments of the apparatus,
systems, and methods in accordance with the present invention, as
represented in the drawings, is not intended to limit the scope of
the invention, as claimed, but is merely representative of various
embodiments of the invention. The illustrated embodiments will be
best understood by reference to the drawings, wherein like parts
are designated by like numerals throughout, and trailing letters
following a numeral simply indicate specific instances of the item
identified by the corresponding reference numeral.
[0051] Referring to FIG. 1, an apparatus 10 or system 10 in
accordance with the invention may include a pump 12 operating as a
delivery mechanism 10 for a fluid. The fluid may typically be of a
viscosity in a configuration suitable for pumping. Likewise, a
fluid may be configured as a liquid having an active ingredient
dissolved within the liquid, or suspending as a micro-pulverized
particulate, all disposed within a liquid having a viscosity
selected to optimize performance of the apparatus 10. For example,
in one embodiment, the fluid or liquid operating within the pump 12
as a fluid may have a viscosity ranging from a very thick,
honey-like substance, to a comparatively aqueous like viscosity,
such as water or other liquid base.
[0052] In another embodiment, the fluid may be a gel containing
gelatin or other gelling agents in a liquid solution to stabilize
that solution against separation, evaporation, or the like.
Accordingly, a medicament or active ingredient may be dissolved in
a liquid, and the liquid may be stabilized with a gelling
agent.
[0053] The active ingredient may include at least one composition
chosen from an antimicrobial, an antibiotic, an antifungal, an
antiviral, an antiseptic, and an antibacterial agent. The active
ingredient may also include at least one composition chosen from an
analgesic, a palliative, and an anti-inflammatory agent. In one
embodiment, the active ingredient comprises at least one
composition chosen from de-ionized water, a polymeric gel, a saline
composition, and a hydrocolloid. The active ingredient may comprise
at least one beneficial agent chosen from an enzymatic debrider, a
tissue growth factor, a scar-reducing agent, tissue cells, topical
nutrients, a coagulant, nitric oxide, oxygen gas, ozone, and a gene
therapy agent. It will be appreciated by those of skill in the art
that the active ingredient may be selected to be therapeutically
effective in treating a dermatological disorder chosen from a skin
defect, an allergy eruption, a skin cancer, a rash, a burn, a
growth, a cyst, a wart, a tumor, an ulcer, a boil, an incision, a
graft, oiliness, dryness, wrinkles, blemishes, discolorations,
trauma, and numerous other maladies or conditions.
[0054] In general, an apparatus or fluid delivery system 10 may
operate to deliver a fluid through a feed conduit 14 extending a
distance appropriate to service a dressing 16. In certain
embodiments, the fluid delivery system 10 may include a housing 18.
The housing 18 may be made of any suitable material and
manufacturing method. For example, various polymers may be formed
by methods such as vacuum forming, injection molding, blow molding,
casting, or the like in various suitable shapes to have an interior
cavity of suitable shape.
[0055] The housing 18 may be made in one or more parts. For
example, the housing 18 may be opened like a clam shell.
Alternatively, the housing 18 may be formed as a single piece. In
other embodiments, the housing 18 may be formed as a single piece
having hinge portions and latch portions in order to close the
housing 18 portions upon themselves in order to enclose the
contents thereof.
[0056] The housing 18 may be formed as pieces, fabricated and
assembled to be permanently closed. The housing 18 may also be
manufactured by stamping, die casting, centrifugal casting,
investment casting, or other methods used in forming polymers or
metals.
[0057] The housing 18 may be formed to have an opaque appearance on
one or both sides or halves, or may have a translucent or even
transparent appearance. In a transparent configuration, the housing
18 may provide visibility of a fluid therein. Thus, a quick, visual
inspection may provide feedback on whether the amount or condition
of the fluid is suitable. Likewise, any malfunction or abnormality
of operation of the pump 12 may be readily visible within the
housing 18.
[0058] Polymer resins for injection molding may provide a
comparatively lightweight and rigid structure for the housing 18.
Likewise, however, various stamped or die cast metal parts may also
provide a robust, rigid, strong housing 18 for containing
pressurized fluids in containers. For convenience, having a
comparatively small aspect ratio of thickness to length or of
thickness to height, in housing 18, may benefit from a
comparatively thicker wall.
[0059] Nevertheless, if a sufficiently light and strong material
and construction configuration are used for the housing 18, an
aspect ratio near unity may be appropriate as containment. For
example, a hard, rigid housing 18 may provide protection against
rupture or failure under the influence of accidental
over-pressurization. This may be important in preventing an
accidental bolus from being delivered due to crushing or
compression of a compressible container within a compressible
housing 18.
[0060] Nevertheless, such a safety or control issue may not be a
problem when a housing 18 is connected by a clip or magnet to a bed
frame, medical IV stand, or the like. Then, a simple containment
vessel of a sack type or wire frame type may suitably act as a
housing 18. On the other hand, a housing 18 may be exposed to
pressure by being placed on the bed or under the pillow of a
patient or in a pocket of the clothing worn by a patient. Then, the
dynamics may dictate the necessity of a rigid housing 18 capable of
withstanding external pressures.
[0061] In the illustrated embodiment, a gas generator 20 may
provide an integrated source of gas to fill a reservoir 22. For
example, the gas generator 20 may include an electrochemical cell.
In one embodiment, the fluid delivery system 10 includes a galvanic
cell in communication with the reservoir and comprising a chemical
selected to produce a gas within the reservoir 22. Thus, a galvanic
cell, in which a galvanic reaction occurs generating gas as a
byproduct of the chemical reaction, is a suitable mechanism for a
gas generator 20. In such embodiments, a control circuit may be an
integrated portion of the gas generator.
[0062] In certain embodiments the gas generator 20 may be enclosed
completely with the reservoir 22, thus easing the need for complex
or unreliable sealing procedures and materials. That is, sealing
different materials or hard materials to flexible materials, or the
like may sometimes be problematic. Likewise, over time, seals may
deteriorate, separate, or otherwise fail.
[0063] By contrast, if the gas generator 20 is integrated within an
electrochemical cell, but then completely encapsulated within the
reservoir 22, a switch or controller may be imbedded. Access may be
obtained by applying pressure to the switch or controller through
the wall of the reservoir 22, by pushing on it through an opening
in the wall of the housing 18. In such a manner, control of the gas
generator 20 may be exercised within a sealed system of the
reservoir 22. Alternatively, a switch mounted to a circuit board is
sealed contiguously onto the face of the reservoir 22 in such a
manner to maintain the gas tight property of the reservoir 22. In
certain embodiments the galvanic cell is enclosed in the reservoir
22 and the wires from the cell where connected to the circuit board
positioned on the housing 18 wall allowing easy access to the
circuit board.
[0064] An electrical conductor having various elements of control
may run the galvanic cell to complete the circuit between the two
reactant materials. A controller may be connected to the galvanic
cell in a circuit to control the generation of the gas in the
reservoir 22, thereby controlling a delivery rate of the fluid from
the fluid source. The controller may comprise a fixed or variable
resistor and a switch. Control may be exercised by something as
simple as a resistor on a switch or something as sophisticated as a
microprocessor-controlled circuit operating based on a
sophisticated, programmed application. For example, the controller
may include a processor programmatically controlling the value of
resistance in the circuit. The fluid delivery system 10 may also
include a sensor (not shown) operably connected to provide inputs
to the processor to control the value of resistance in accordance
with an algorithm therewith.
[0065] In one embodiment of the fluid delivery system 10 at least a
portion of the controller is located separately from the galvanic
cell and is in communication with the cell by at least one of
mechanical hardware, electromagnetic, radio frequency, magnetic, or
optical feedback or circuit. In other embodiments, the controller
is located inside the reservoir 22.
[0066] In operation, the gas generator 20 acts to fill the
reservoir 22 in a controlled manner. Accordingly, the reservoir 22
will expand with the volume and pressure of the gas generated by
the gas generator 20. Accordingly, the reservoir 22, contained on
one side by a shell 24 or half 24 of the housing 18, may expand to
displace the fluid source 26. The fluid source 26 in contact with
the reservoir 22 is thus compressed between the reservoir 22 and a
wall of the housing 18, resulting in expression of the fluid.
Accordingly, the housing 18, together with the reservoir 22 and the
fluid source 26 may be referred to throughout the specification as
a pump 12.
[0067] The fluid source 26 within its shell 28 or half 28 of the
housing 18 may actually contain any type of fluid. In one example,
gas, liquid, or gel of suitable consistency and chemical
composition may dispense from the fluid source 26.
[0068] In certain embodiments, a fluid may be loaded in the fluid
source 26 at a manufacturing plant. The fluid source 26 may there
be sealed to maintain a sterile condition until use. In an
alternative embodiment, the fluid source 26 may be filled on site
or at point of use by a doctor, pharmacist, or other medical
professional responsible.
[0069] Either factory filling or onsite filling may use a fill port
30. Cost and security for a pre-filled fluid source 26 may militate
against having a fill port 30. However, for a fluid source 26
designed to be filled or at point of use, a fill port 30 may be
provided with an access 32 or inlet fixture 32. In one embodiment,
the access 32 may be a septum 32 through which a syringe may
penetrate to fill the fluid source 26. The fill port 30 may be made
of a material of sufficient hardness and length to receive a needle
without risk of puncture. The fill port or may alternatively be a
luer lock type.
[0070] The fluid source 26 may be formed of any material that will
contain the liquid but not actively affect the contained fluid, for
example, polyethyleneteraphthalate (PET). In certain embodiments,
various other polymers such a polyethylene, polypropylene,
polyvinylchloride, or the like may be suitable. However, in
general, the nature of the material of the fluid source 26 should
not admit any harmful substances or reactions to the contained
fluid.
[0071] This is particularly important for situations where the
fluid source 26 may sit on a shelf, filled with a fluid, for a
considerable period of time. For example, in a factor-sealed fluid
source 26, the shelf life of the fluid must be configured along
with the shelf life of the chemical constituents, plasticizers, and
other chemicals that may be leached from the wall of the fluid
source 26 into the fluid of the fluid.
[0072] In one embodiment of a method and apparatus in accordance
with the invention, a medical professional may draw a fluid into a
syringe. The syringe may be fitted to a needle or other injector to
penetrate the septum 32 or access 32 to the fill port 30. A
suitable amount and concentration of a prescribed fluid may fill
the fluid source 26 to a suitable level required to service the
dressing 16 for a predetermined time.
[0073] The volume added to the fluid source 26 may completely fill
the fluid source 26. Alternatively, the amount of the fluid added
to the fluid source 26 may exceed the capacity thereof. For
example, the apparatus 10 may be "jump started" by adding a bolus
of fluid to fill the fluid source 26, the feed conduit 14, and some
portion or all of the dressing 16. Thus, the dressing 16 may be
pre-loaded or even pre-saturated by a fluid when first loaded.
Repeated boluses are possible.
[0074] Likewise, in certain embodiments, the apparatus 10 may be
filled by an individual patient. For example, many superficial
wounds such as scrapes and lacerations may benefit from an
over-the-counter (OTC) solution, salve, oil, antiseptic, antibiotic
or the like. Accordingly, an OTC version of the apparatus 10 may be
either pre-filled or filled by a user with an OTC fluid.
[0075] In service, the apparatus 10 may feed a fluid from the fluid
source 26 out through an exit port 34. The exit port 34 may be
provided with a fitting 36 adapted to accomplish one or several
functions. For example, the fitting 36 may include a check valve to
prevent any back flow of the fluid from the feed conduit 14 into
the fluid source 26. Likewise, the fitting 36 may include an
orifice or other metering device to limit the flow of fluid to a
particular rate.
[0076] A regulator, check valve, or pressure-relief valve may be
part of the fitting 36 to maintain a certain pressure within the
fluid source 26. The regulator may be outside of, partially within,
or completely within the fluid source 26. Pressure in the fluid
source 26 may be particularly important to precise control of
delivery. It may need to increase when operating with particular
fluids. Perhaps most frequently, regulation of pressure may resist
wide fluctuations in the rate of delivery of the fluid.
[0077] For example, barometric pressure, ambient temperature, and
the like may directly affect the pressure of gas in the reservoir
22. Wide fluctuations in either may be counter-productive to
precise metering of a fluid through the fitting 36. If a
pressure-regulation valve is located within the fitting 36, or
otherwise associated therewith, comparatively higher pressure
reduces sensitivity of the fluid source 26 or reservoir 22 to
ambient pressure and temperature. For example, a bolus dose is not
administered simply as a result of an increase in ambient
temperature increasing the volume of the gas in the reservoir
22.
[0078] Thus, in one embodiment, the fluid source controls a fluid
flow to dressing 16 or to a distribution member 40. The flow rate
may be continuous or discontinuous. A discontinuous flow rate may
be one that turns off and on over a period of time. A discontinuous
flow rate may also be one provided under the variable force of a
syringe. In one embodiment, flow rate may be programmatically
controlled by a controller. The program may account for fluid flow
patterns, either pre-selected or arbitrary, valve, conduit size,
and other flow control parameters.
[0079] In general, an aperture 38 in either shell 24 of the housing
18 may provide access to a button to control operation of the gas
generator 20. The aperture 38 may be closed with a cover, seal,
diaphragm, or the like. For example, a rubber cover may fit within
the aperture 38 resisting entry of dirt, dust, moisture, and the
like into the housing 18. Nevertheless, a cover of thin, flexible,
elastomeric material allows a user to apply pressure to a control
button of the gas generator 20.
[0080] In certain embodiments of an apparatus and method in
accordance with the invention, a cover member 39 or protective
member 39 of a dressing 16 may provide one or more useful
functions. For example, the protective member 39 may be opaque in
order to prevent unsightly appearance of the dressing 16. By the
same token, the protective member 39 may be transparent in order to
provide easy monitoring. One may observe direction the distribution
of the fluid throughout the dressing 16, as well as any seeping of
blood or serum back into the dressing 16 from a skin defect being
treated.
[0081] Likewise, a protective member 39 may typically resist
abrasion, snagging, and other contact or contamination damage to
itself and the underlying distribution member 40. Other members may
exist within a dressing 16. Nevertheless, a protective member 39
may resist abrasion, transport of fluid, dirt, puncture, or the
like. Likewise, the protective member 39 may be perforated or
porous to permit access of air to a dressing 16.
[0082] The protective member 39 may be liquid proof to prevent
escape or wicking of a fluid or other liquid in the dressing 16
into clothing, bedding, or the like. In certain embodiments, the
protective member 39 may be microperforated or formed of some
suitable material that permits passage of oxygen, water vapor or
other gases while resisting passage of liquids.
[0083] Typically, a distribution member 40 holds a fluid delivered
from the fluid source 26 through the feed conduit 14. The porosity
of the distribution member 40 provides distribution of
comparatively aqueous like fluids throughout. Meanwhile, the
generation of gas from the gas generator 20 into the reservoir 22
applies both pressure and volume variation into the fluid source
26, driving a flow of fluid at some desired, engineered rate into
the dressing 16. Thus, the fluid source may control the fluid flow
to the distribution member 40. In one embodiment, the feed conduit
14 is connected to the fluid source 26 for replenishing the fluid
in the distribution member 40, with or without additional human
intervention.
[0084] The housing 18 may be relieved at selected locations to
form, for example cradles 42, 44 capturing the fill port 30 and
exit port 34, respectively. The cradles 42, 44 thus permit location
of the access (inlet) fitting 32 and outlet fitting 36 outside the
housing 18. The fitting 36 may be adapted to fit into or around the
feed conduit 14.
[0085] The feed conduit 14 may feed into a feed line 48 passing
into the dressing 16. An inlet port 50 the center of the area of
the dressing 16 may distribute the fluid throughout by capillary
action the distribution member 40 of the dressing 16. In certain
embodiments, a manifold (not shown) may be used. Without a tailored
capillary capability in the distribution member 40, distribution of
a fluid throughout the dressing 16 may be enhanced by distributing
throughout the distribution member 40 through a manifold. The
manifold may be configured in any suitable manner. It will be
appreciated by those of skill in the art that the feed conduit may
be part of the dressing 16 itself.
[0086] For example, a large plenum having substantial area or a
long linear path may present little resistance to flow of the
fluid. A larger pressure drop would then occur as the fluid exits
through perforations or other flow-limiting orifices.
Alternatively, a manifold may have apertures sized to control or
balance out pressure along several paths of distribution through
tubes within the manifold. These apertures may provide the major,
substantial, pressure drop between the pressure upstream of the
manifold, and the ambient pressure in the dressing 16.
[0087] Referring to FIG. 2, various embodiments of the housing 18
may capitalize on manufacturing methods, optimization of costs,
ease of manufacturing, simplicity of operation, weight, shape, or
the like. For example, the housing 18a provides an aspect ratio of
thickness to width or thickness to height sufficiently small to fit
readily into a pocket. Thus, an active outpatient, wearing of a
dressing 16 may remain active. A comparatively thin, unobtrusive,
housing 18a fits easily into a pocket of any article of
clothing.
[0088] Likewise, the housing 18b may have a lightweight, clam shell
configuration. A lattice 54 sufficient to contain the reservoir 22
and fluid source 26 may not provide puncture proofing for reservoir
22 and fluid source 26. However, if puncture is not a practical
threat to the integrity of an apparatus 10, the lattice 54 may
provide an appropriate wall. The housing 18b reservoir 22 and fluid
source 26 are not shown, for clarity, but may fit the gas generator
20 and the inlet fitting 32 and outlet fitting as with the housing
18a.
[0089] Each of the housings 18 may be made of suitable size to
match the administration of a fluid, ease of use, and carriage
needs. For example, a comparatively thinner housing 18 may operate
best when the reservoir 22 and fluid source 26 are placed side by
side. If the reservoir 22 and fluid source 26 are placed end to end
as in the housing 18c, then the aspect ratio of width to thickness
at one end 56 of the housing 18c may be closer to one. The length
of the housing 18c may be selected to promote complete expansion of
the reservoir 22 and fluid source 26. The gas generator 20 filling
the reservoir 22 may have a button on the outer wall of the housing
18c, or on one end 56. Alternatively, access to the gas generator
button may be on the same end of the housing 18c as the inlet
fitting 32 and outlet fitting 36.
[0090] In all the embodiments illustrated, the inlet fitting 32 is
optional, depending upon whether a fluid is pre-loaded and sealed
into a fluid source 26 by a manufacturer. If the fluid source 26 is
filled or refilled at the point of use some access fitting 32 is
required. However, the housing may be refillable with a pre-filled,
sealed reservoir 22 and fluid source 26 in some embodiments.
[0091] The housing 18d may have a rounded, oblong cross section, an
oval cross section, or a circular cross section. One benefit of a
right circular cylinder shape is minimizing the overall dimensions
of the housing 18d. Greater volume requires less surface area
material if shaped like a sphere. Other shapes are improved as all
the aspect ratios of thickness, to width, to length approach unity.
Thus, a sphere is capable of holding the maximum volume with the
minimum area of wall. Likewise, a right circular cylinder provides
a better or greater volume per unit of area of wall then does a
rectangular container. Nevertheless, various considerations,
including convenience, mobility, and the like may be used to
determine what shape, aspect ratios, and materials may be used in
each of the housings 18.
[0092] In certain embodiments, the housing 18e may be formed of one
or more lightweight materials and may even be flexible. For
example, the housing 18e may actually be formed of a sparse lattice
work of a polymer or fiber-reinforced polymer to sustain only
internal pressure, not external pressure. Alternatively, the
housing 18e may be formed as a filament-wound composite material of
resin and reinforcing fibers having comparatively (compared to
volume changes of liquid with ambient temperature, for example)
very rigid walls in tension and compression, even sustaining very
high pressures of many atmospheres.
[0093] For example, in certain embodiments, the exit port 34 may
include a fitting 36 containing a tiny orifice sized to meter flow
of a fluid. The housing 18e may sustain pressures of several
atmospheres. At higher operating pressures than atmospheric, the
effects of barometric or other environmental pressures and
temperatures are significantly reduced. The housing 18e may have
aspect ratios of a pocket pen, or small pocket accessory. A
retainer 58 or clip 58 may secure the housing 18e to a pocket,
clothing, bedding, or other suitable location. Engineered selection
of aspect ratios of diameter to length for any housing 18 may
promote unobtrusive location in clothing, bedding, or the like.
Reliability of sealing and operation of the reservoir 22 and fluid
source 26 has advantages with circular seals.
[0094] The housing 18f has an advantage of providing no substantial
corners and a comparatively small aspect ratio of thickness to
diameter, suitable for carrying in a purse, pocket, or the like.
Meanwhile, manufacturing of the reservoir 22 and fluid source 26
may be simplified, and sealing thereof readily adaptable to various
manufacturing processes.
[0095] Referring to FIG. 3, a feed conduit 14 may optimize any
parameter affecting cost, deployment, operation, durability,
reliability, or the like. In the illustrated embodiments of FIG. 3,
feed conduits 14 may have a round, or comparatively flat aspect.
For example, the feed conduit 14a may include a very inexpensive
bottom layer 62 and top layer 64 sealed together along a flange
portion 66. The interior 60 of the feed conduit a may be completely
empty, forming a tube. The feed conduit 14a may be formed of
plastic film, plastic-coated paper, foil-coated plastic, or the
like. Accordingly, the feed conduit 14a may be provided in a
roll.
[0096] Alternatively, the feed conduit 14a may be cut to length or
have fittings on either end preformed to interface with the outlet
fitting 36 and the feed line 48 of a dressing 16. A fixture adapted
to the outlet fitting 36 or feed line 48 may speed handling,
connection, and sealing. In yet another alternative, the fluid
source 26, feed conduit 14, and dressing 16 may be formed as an
integrated, connected unit for disposable use. For example,
polymer-coated paper may serve the structural and protective
functions of all three components.
[0097] In one embodiment the feed conduit 14 may be filled with a
core 60 or the like. For example, the cross-sectional area compared
to the length of the feed conduit 14a may be extremely small. The
flanges 66 may more easily sustain internal pressure, if enclosed
volume is minimized within the feed conduit 14a. This corresponds
to a filled cross section that is round or square and relatively
small.
[0098] A core 60 may provide wicking from the outlet fitting 36 to
the dressing 16 for several reasons. For example, in certain
embodiments, pressure drop through the length of a feed conduit 14
may be desirable. By providing a rather tortuous path in a core 60,
pressure in the fluid source 26 is not the direct driving force for
transport. Rather, evaporation in the dressing 16 may draw the
fluid by capillary action, replenishing liquids. Thus, the core 60
may provide regulation and replenishment automatically as
needed.
[0099] Evaporation of liquid from a dressing 16 may provide a means
of replenishment of the active suspended or dissolved therein.
Thus, one way to assure an adequate concentration of an active
ingredient in the fluid in the dressing 16 is to provide a
comparatively volatile liquid that will evaporate from a dressing
16. Accordingly, as the carrier liquid evaporates, the fresh fluid
is drawn in, having the concentration available from the fluid
source 26.
[0100] In certain embodiments, the entire dressing 16, feed conduit
14, and fluid source 26 may be embodied in a single integrated
system 70. For example, the volume 68a may be directly formed or
sealed at a factory as a fluid source 26 to be placed in the
housing 18 with the feed conduit 14b protruding there from. The
feed conduit 14b may then conduct the fluid toward a header 50 or
manifold 50 servicing a dressing 16 embodied as the distribution
member 68b. It will be appreciated by those of skill in the art
that the distribution member 68b may be designed or have the same
characteristics as the distribution member 40 discussed above. The
entire system can be sealed at a factory, and filled at point of
use, or filled at the factory.
[0101] If filled at the factory, a seal may be required to close
the reservoir 68a against leakage into the feed conduit 14b. If
filled at point of use, the entire assembly may be shipped dry. The
disposable fluid source 26, 68a may be filled at point of use
including optionally priming both the feed conduit 14b and the
distribution member 68b of the dressing 16, as desired. The end 68b
may be an entire dressing assembly 16, including a distribution
member 40.
[0102] The feed conduit 14b illustrates one embodiment in which the
feed conduit 14 may be rolled flat. The entire assembly 70 may be
rolled flat together or rolled together about the distribution
member 40, 68b or dressing 16, 68b. The feed conduit 14b may be
formed of any suitable material, whether paper, film, foil, other
laminates, or the like. Meanwhile, in the illustrated embodiments,
the feed conduit 14b may be have an integrated distribution member
68b or dressing 68b. The distribution member 68b may be fed
directly by the feed conduit 14b, or by the feed conduit 14b
through a manifold 50. Likewise, the distribution member 68b may be
the same as a wicking layer 14 of a dressing.
[0103] For example, in certain embodiments, the dressing 16 may be
formed flat of plastic film, plastic-backed paper, foil-lined
paper, or foiled plastic. The distribution member 40, 68b or
perhaps the entire dressing 16, 68b, may be formed integrally at
manufacture with the feed conduit 14b. When the dressing 16, 68b is
packaged, it may be sealed up and maintained sterile along with its
entire feed conduit 14b.
[0104] If an integrated dressing 70 is formed to include the fluid
source 26, 68a, distribution member 40, 68b and intervening feed
conduit 14b, deployment may be simplified. Upon deployment, no
sealing or connection is needed between the fluid source 26, 68a,
feed conduit 14b, and the distribution member 40, 68b or dressing
16, 68b.
[0105] Fittings may be adapted to the feed conduit 14b to readily
connect or may be unnecessary by forming all as a single
containment. Upon opening, the integrated system 70 provides a
fluid source 26, 68a fitting within the housing 18, a feed conduit
14b exiting through an appropriate cradle 44, and a distribution
member 40, 68b or dressing 16, 68b at the opposite end.
[0106] A simply activated or rupturable seal may secure the fluid
source 26 against any transfer of fluid to the feed conduit 14b
prior to application. In one embodiment, the outlet fitting 36 may
be combined with the access fitting 32. For example, injection
through a septum 32 may provide piercing of a plastic seal to the
fluid source 26 in order to permit filling, or simply to permit
emptying. Thus, whether pre-filled or filled at point of use, the
fluid source 26 may be connected to the feed conduit 14b as an
integrated assembly relying only on the housing 18 and gas fluid
source 22 supplied also at point of use.
[0107] In certain embodiments, tubing 14c may provide a feed
conduit. Such tubing may be provided on a reel 69 in bulk, or in a
coil suitable for implementation as a plumbing project at point of
use. In certain embodiments, the fitting 36 may easily be connected
to a feed conduit 14c formed of a polymer or elastomer suitable to
form a sealed, snug fit with the fitting 36. Likewise, the feed
line 48 may provide sufficient structural stiffness, elasticity, or
both to receive a feed conduit 14c snugly fitted there around.
[0108] The feed conduit 14d may be formed as flat tubing formed of
a plastic film, elastomeric material, treated paper, plastic film
reinforced by paper, or the like. In the illustrated embodiment,
the feed conduit 14d may be provided with tips 72 or fittings 72 to
act as seals, and as spreaders to open the feed conduit 14d. The
fittings 72 support connection of the feed conduit 14d to the
fitting 36 of the pump 12, as well as to the feed line 48 of the
dressing 16. A predetermined length of feed conduit 14d may
minimize cost and still maintain reliable sealing between the feed
conduit 14d and its associated fitting 72a, 72b. The fittings 72
may provide a very low cost solution to delivery of fluid from the
fitting 36 to the dressing 16.
[0109] Referring to FIG. 4, the geometry of a dressing 16 may be
configured for generic or specialty purposes. For example, in
certain embodiments, a dressing 16a may be formed in a cylindrical
configuration. A bulky shape may be required to fit within a wound
that must heal itself closed, rather than be sutured closed.
[0110] In accordance with certain aspects of the invention, various
layers 76, 77, 78 may provide differing benefits. For example, an
interface member 78 may be provided as a non-adhering layer. For
example, under the brand name TELFA.TM. a micro-perforated
non-adhering polymer film is used in bandages. A TELFA.TM. layer
may be appropriate for the interface member 78. In one embodiment,
the interface member 78 is or contains a non-adhering polymer. In
another embodiment, the interface member 78 may be or contain a
bioabsorbable polymer. In one embodiment, the interface member 78
includes one or more of the following structures, either alone or
in combination: a sheet, foam, a gel, gauze, a porous matrix, a
honeycomb, a mop of fibrous material, a comminuted fibrous
material, and a tubular structure. It will be appreciated by those
of skill in the art that the interface member 78 may be made of
other materials known not to adhere to a skin defect.
[0111] In one embodiment, the interface member 78 is a
self-destructive material that can peel away from an adjacent layer
or member, such as the distribution member, when the dressing 16 is
removed from the skin defect and be left behind on the skin defect.
For example, in one embodiment, a gel may control adhesion and
self-destruct to prevent adhesion, so long as properly hydrated by
the fluid. In other embodiments, the interface may be dissolvable
or absorbable over time. The interface member 78 may also be
configured to separate from the skin defect when the dressing is
removed.
[0112] Meanwhile, the distribution member may comprise a "smaller
pore size" wicking layer 77 that may distribute a fluid to skin
defect through or without an interface member 78 and a "larger pore
size" an inner layer 76 that may transport fluid by capillary
action also, but with less resistance to flow. Nevertheless, the
higher effective distance (larger pore size) across porosity in an
inner layer 76 may provide less orientation-independence.
[0113] Likewise, a difference in pore size provides a net draw of
liquids from areas of larger pore size to areas of smaller pore
size. Thus, an inner layer 76 may receive a fluid from the feed
line 48a. Accordingly, the inner layer 76 may distribute readily
the fluid to the principal wicking layer 77. The principal wicking
layer 77 may assure even distribution thereof.
[0114] Likewise, the dressing 16b may be configured geometrically
to fit any particular application. Typically, wounds that are not
of a serious or persistent nature may be closed by suturing. By
contrast, chronic wounds, and wounds that may be subject to
infection may be allowed or required to heal themselves closed, or
may be closed only after infection has been eliminated or
sufficiently reduced. Accordingly, a dressing 16b may be formed to
fit within an open wound, thus delivering fluid by contact against
the deep, affected, open surfaces of the wound.
[0115] The manufacture of the dressing 16b may begin with a
cylinder, such as the layered cylinder of the dressing 16a. The
cylinder 16a may then be molded, embedded with holding agents,
stitched, heat set, or otherwise shaped as desired. Accordingly,
the features of the dressing 16a may be implemented in a dressing
of the configuration of the dressing 16b illustrated. Many
specialty shapes may be made in this way to fit specific needs.
[0116] Many dressings are applied to surfaces covering and
surrounding skin defects or wounds. For example, an injury may
cause an open cut, laceration, scrape, burn, or the like. Likewise,
an incision may leave a wound to be healed. In other circumstances,
sores, boils, or the like may result in an open wound. The wound
itself may need access to a fluid, but the surrounding area may
also need a different treatment.
[0117] The area of a dressing 16c may be subdivided into regions.
For example, a central region may contain the wound, and a
surrounding area may be clear. In certain embodiments, two separate
feed lines 48c may be provided to address two separate areas of a
dressing. For example, if a wound itself needs an antibiotic, but a
surrounding area needs an antiseptic, both may be delivered to
different portions of a dressing 16c or two different dressings
16c.
[0118] In certain embodiments, a dressing 16c may receive a fluid
through a feed line 48c into a plenum 82. The plenum 82 may act as
a manifold 50 feeding various runs 84 or arms 84 distributing a
fluid to the farther reaches of the dressing 16c. In the
illustrated embodiment, the protective member 39 is shown as
transparent in order to view the plenum 82 and runs 84.
[0119] As discussed hereinabove, the protective member 39 may be
opaque, transparent, thin, thick, or otherwise configured to
accomplish its function. Functions may typically be selected from
preventing evaporation, promoting evaporation, providing resistance
to abrasion, puncture, or other damage, providing access to air,
providing protection from air, and so forth.
[0120] In the arms 84 or runs 84 off the plenum 82, perforations or
other apertures may be selectively distributed. In certain
embodiments, the entire network 80 may be porous yet resistant to
leakage. For example, each of the plenum 82 and the runs 84 may be
full of liquid dispensed only slowly and evenly throughout the
dressing 16c via micropores driven only by pressure from the fluid
source 26.
[0121] In other embodiments, the plenum 82 and arms 84 may actually
be distribution tubes sized to receive and pass a liquid or other
fluid readily, yet be sealed along their entire lengths except for
an aperture at the end thereof. In certain embodiments, a dendritic
or branching structure of the arms 84 may take on any suitable
shape, whether rectangular, triangular, circular, polygonal,
repeated bifurcating, or the like, and may branch sequentially any
number of times.
[0122] For example, in certain embodiments, a tree structure may
have a trunk or plenum 82, in which the branches 84 or arms 84
branch from one another, thus providing a network of distribution
tubes. In certain embodiments, ends of the arms 84 may be drawn
down or restricted in some other way in order to equalize pressure
throughout, and provide control and distribution at an even rate
throughout all of the end points or tips of the arms 84 throughout
the dressing 16c. The distribution member 40 is then responsible to
distribute from the arms 84 throughout itself in order to maintain
a distribution of the fluid.
[0123] In general, the dressing 16d may include a protective member
39, a distribution member 40, and any other members need for
distribution, promotion of flow, protection from outside
environmental influences, protection against adhesion with the skin
defect, or the like. Meanwhile, after penetration by the feed line
48d, the distribution system within the dressing 16d may take on
any suitable form, such as those illustrated in FIG. 5.
[0124] Referring to FIG. 5, various embodiments of a dressing are
illustrated. For example, the dressing 16e may actually contain a
distribution member with a layer fed by a manifold 50 contiguous
and continuous with a core 60 of a feed conduit 14. For example,
the feed conduit 14a of FIG. 3 provided an upper layer 64 and base
layer 62 sealed to form a feed conduit there between. Either a
cavity or passage may be provided or a wicking core 60.
[0125] In certain embodiments, a dressing 16f may be formed with a
membrane 86 forming either a protective member, or a pocket. In
certain embodiments, the membrane 86 may be formed as an envelope
having distribution openings on the underside thereof against the
distribution member 40 of a dressing 16f. For example, the feed
line 48 may feed into a pocket-like membrane 86 having porosity
only around the underside edges thereof. Likewise, the edges
themselves may simply be perforated with small perforations tending
to render the membrane 86 a large plenum.
[0126] The membrane 86 or membrane pocket 86 may be tacked through
at certain location across its area, in order to prevent it from
inflating in response to the pressure and presence of a fluid
therein. Likewise, suitable perforations or other porosity may be
sized and distributed across its underside, around its periphery,
or along the perimeter of its underside in order to deliver a fluid
into the underlying dressing 16f, or into the distribution member
40 of the dressing 16f.
[0127] The dressing 16g may include a protective member 39, and an
underlying interface member 88. Between the protective member 39
and the interface member 88 may be a wicking material suitable for
the function. Meanwhile, the feed conduit 14 may feed into the
dressing 16g while the dressing itself passes fluid through the
microporosity of the interface member 88.
[0128] In an alternative embodiment, for which the dressing 16g may
also serve as an illustration, the protective member 39 of the
dressing 16g may be the wick portion, while the interface member 88
serves as a plenum having a distribution of perforations to feed
the fluid into the protective member 39. In accordance with the
invention, a feed conduit 14 may feed into the interface member 88
formed as a hollow, flat, tube perforated to feed a protective
member 39 which may be the wicking layer in this embodiment
associated with the dressing 16g. In such an embodiment, a closed,
flat, tubular membrane 88 may be perforated on one or both sides to
feed into a distribution member 40. Thus, rapid distribution occurs
along the comparatively larger volume available in flat tube 88.
The tube 88 acts as a plenum 88, providing the fluid to the
perforations crossing into the wicking layer, here represented by a
protective member 39. Other members may be present in addition for
other functionality as discussed hereinabove.
[0129] The dressing 16h formed of a wicking material such as a
fiber, fabric, gauze, foam, or other material may be used alone.
Alternatively, it may be used to assemble a dressing. In yet
another embodiment, it may be located inside other members, such as
between a barrier member and a non-stick member shown in FIG. 7.
Accordingly, a full-width manifold 50 may provide an even
distribution from an edge of a distribution member 40. The
distribution member 40 may be engineered to standard or custom
shapes, areas, thicknesses, widths, and lengths to meet the flow
demands of a fluid to a particular skin defect. Sizes and shapes
may include circular, rectangular, or cut-to-order for particular
injured areas. In one embodiment, the distribution member 40 is
configured to be cut to a desired size and still maintain a
substantially uniform volume of fluid across the distribution
member 40. Accordingly, in one embodiment, a cross-section of the
distribution member is substantially the same and any other
cross-section of the distribution member. It will be appreciated by
those of skill in the art that multiple layers or members of the
dressing 16 may cut individually or collectively to customize the
size of the dressing 16.
[0130] In one embodiment, a dressing 16j may feed a distribution
member (not shown) opposite a protective member 39. For example, a
distribution system 80 or distribution tubes 80 may include a
plenum portion 82 as well as various arms 84. In the dressing 16j,
the plenum 82 or even the entire distribution network 80 may be
formed of two layers of film. The side of the film fitted against
the distribution member may have microperforations 90 sized to
provide an even distribution.
[0131] The placement, size, and number of the perforations 90 may
control the pressure drop from within the plenum portion 82 into
the distribution member 40. Typically, however, the pressure
differentials between the plenum portion 82, and the inside of the
arms 84 may be comparatively quite small compared to the pressure
difference between a fluid source 26 and a plenum 82. Accordingly,
the distribution pattern of the perforations 90 may provide a
limited number of outlets to control distribution into a
distribution member 40.
[0132] In certain embodiments, a dressing 16k may have spiraling
distribution tubes 80. For example, the distribution tubes 80 may
be perforated along its entire path. The distribution tubes 80 may
be configured as a spiral having a continuously decreasing
cross-sectional area. Alternatively, the size of the internal
diameter of the distribution tubes 80 may be constant, but the
perforations may be comparatively smaller. Thus, the distribution
tubes 80 become a plenum feeding out the fluid into the
distribution member 40.
[0133] The distribution tubes 80 may have branches extending from
the spiral. On the other hand, manufacturing may dictate a very
simple configuration. Accordingly, a constant diameter and regular
perforations of suitable size and distributed along its continuous
length may operate adequately. Sealing one end of a perforated
tubing, with the opposite end serving as a feed line 48 may provide
a completely serviceable distribution tubes 80.
[0134] In certain embodiments, a dressing 16m may have a serpentine
distribution tubes 80. Again, the serpentine shape may be formed of
commercially available tubing, flat tubing, a pocket between layers
of film or other material, or the like. Pressure drops may be
engineered from the pressure of the gas in the reservoir 22 through
to the pressure in the fluid source 26 holding the fluid, on to
pressure drops through the exit port 34 and fitting 36 as well as
the feed conduit 14. Meanwhile, the pressure dropped from the feed
conduit 14 into any manifold 50 or distribution tubes 80 and on to
the ambient environment of a dressing 16 may be engineered to make
uniform the distribution in the illustrated embodiments.
[0135] One benefit of an engineered distribution member 40 of
suitably small pore size is an independence from the effects of
orientation. For example, in many circumstances, a dressing is
assumed to lie horizontally. Accordingly, in theory, the entire
dressing is at an even height. Thus, gravity effects do not alter
dramatically the distribution of a fluid there throughout.
Accordingly, the force exerted on the fluid by wicking action would
be greater than or equal to the force exerted on the fluid by
gravity.
[0136] However, in reality, many patients have skin defects located
on vertical surfaces. For example, an outpatient may actually be
active, walking about, engaging in athletic activities, while
having a dressing 16 in place on an arm, leg, foot, torso, or the
like. The effect of gravity is to bring a liquid down to the lowest
contained altitude possible. However, by selecting the pore size,
composition, construction, thereby creating specific
hydrophobic/hydrophilic interactions, surface tension affect, or
capillary force affect of the distribution member 40 an apparatus
and method in accordance with the invention may provide
independence of orientation.
[0137] Referring to FIG. 6, a dressing 16 may comprise a feed
conduit (as shown and described in connection with FIGS. 1, 3, and
5 above) for delivering a fluid to a distribution member. The
dressing 16m 16p, 16q, and 16r and distribution member receive and
distribute the fluid substantially uniformly across the
distribution member, irrespective of the orientation of the
distribution member. The term "substantially uniformly" in relation
to fluid distributed across the distribution member may mean that
fluid is distributed to all parts of the distribution member 16.
This may occur across a particular layer of the distribution member
16 or across all layers of the distribution member 16.
"Substantially uniformly" may also mean that there is not
significant pooling of fluid in one area of the distribution member
while other areas of the distribution member have less fluid.
"Substantially uniformly" may also mean the volume of fluid in one
cross section of the distribution member is similar to the volume
of fluid in other similarly sized cross sections of the
distribution member. "Substantially uniformly" may also mean that
the difference in fluid from section to section across the
distribution member is small enough such that the application of
the dressing 16 to the skin defect will result in consistent
delivery to various areas of the skin defect.
[0138] The material of the distribution member 16 may allow for
movement or the spread of fluid substantially uniformly across the
distribution member by wicking action. The term "wicking action,"
"wicking," or "wick" as used herein throughout may include or may
be used interchangeably with movement of fluid by capillary action,
surface tension, hydrophobic action, hydrophilic action, or similar
types of forces that can move a fluid. Orientation independence for
example, may mean that the dressing 16m may be fed from the top and
oriented vertically. The dressing 16b is oriented vertically, but
fed horizontally, while, the dressing 16q is oriented horizontally
and fed horizontally. The dressing 16r is oriented vertically, and
fed from below. In all of illustrated embodiments in FIG. 6, the
orientation of the dressing 16 may be ineffectual to inhibit
distribution.
[0139] In embodiment, the distribution member comprises at least
one material chosen from a polymer, a woven fabric, a non-woven
fabric, a naturally occurring fiber, a sponge, a fiber matrix, a
gauze, absorbent material, adsorbent material, a gel, and a foam.
In one embodiment, the distribution member 16 is a porous
pouch.
[0140] Within the bounds dictated by physics and engineering, the
capillary action of the distribution member 40 will draw a liquid
upward. Also, "kiss-through" tacking of the outermost members of
the dressing together will resist accumulation within the dressing.
For example, a distribution member 40 may be bonded to a protective
member 39 at regular intervals along a line, across a grid, or the
like. Accordingly, two members not allowed to separate more than a
nominal distance resist fluid accumulation.
[0141] However, by properly sizing the pore size composition,
construction, thereby creating specific hydrophobic/hydrophilic
interactions, surface tension affect, or capillary force affect of
the distribution member 40, a dressing 16 may constructed of the
distribution member 40 to effectively defy gravity and distribute
the medicament, even upward from a location where introduced.
Accordingly, the distribution member 40 may receive and distribute
the fluid substantially uniformly across the distribution member,
irrespective of the orientation of the distribution member.
[0142] In this embodiment, the distribution member 40 maintains a
predetermined amount of fluid substantially uniformly across the
distribution member. The distribution member 40 may in some
configurations release fluid at a saturation point of level of the
distribution member 40. In other embodiments, the release of fluid
by the distribution member 40 may occur before or after that time.
It will be appreciated by those of skill in the art that the rate
and amount of fluid into the distribution member 40, coupled with
the pore size of the distribution member 40 and the structure of
adjacent members may be used to determine at what point the
distribution member 40 may release fluid and also to what extent
the fluid is distributed throughout the distribution member 40. It
will further be appreciated by those of skill in the art that by
having a distribution member configured to uniformly distribute
fluid, or in other words, to have similar amounts of fluid occupy
the different areas of the distribution member 40, that better
application of the fluid to the skin defect can be obtained.
[0143] The distribution member 40 was tested in one test by
applying the dressing vertically to a sheet of glass. An amount of
colored fluid was applied to the center of the distribution member
and the spread of fluid was recorded over time. Viewing the
recording after various points in time revealed that fluid was
radially distributed from the point of introduction uniformly in
all section of the distribution member despite the down ward pull
of gravity. Thus, at different points in time, the outer boundary
of the spreading fluid created substantially concentric circles
under the entire distribution member was filled with fluid. Dozens
of tests were performed with substantially similar results.
[0144] The configuration of the distribution member 40 of the
present embodiment may also allow the distribution member to
maintain a concentration of active ingredient in the fluid
substantially uniformly across the distribution member and allow
said concentration of active ingredient in the fluid to communicate
with the skin defect. The distribution member 40 may be engineered
to allow the concentration of the fluid to be uniformly distributed
across the distribution member. In other words, the distribution
member 40 may allow fluid distribution such that a concentration of
the fluid in one area of the distribution member is substantially
similar to the concentration of the fluid in another area of the
distribution member. By engineering the distribution member 40 and
by choice of active ingredient carrier as discussed above, among
other things, the distribution member may maintain a concentration
of active ingredient in the fluid substantially uniformly within a
predetermined range of concentration across the distribution member
and may allow said concentration in said range to communicate with
the skin defect. In one embodiment, the dressing 16 comprises a
feed conduit for delivering a fluid to a distribution member 40.
The distribution member 40 receives and distributes the fluid
substantially uniformly across the distribution member 40,
irrespective of the orientation of the distribution member 40. The
distribution member 40 comprises material that allows the spread of
fluid substantially uniformly across the distribution member 40 by
wicking action and can be cut to a desired size and still maintain
a substantially uniform volume of fluid across the distribution
member 40.
[0145] Referring to FIG. 7, in certain embodiments, a dressing 16
may include one or many members to accomplish their respective
functions. For example, in the illustrated embodiment, a member 92
may be a protective member 92. Protective members 92 are typically
installed to prevent puncture, abrasion, snagging, evaporation,
wetting, soiling, and the like. A protective member 92 may operate
to provide multiple functions. It will be appreciated by those of
skill in the art that the protective member 92 may be the
protective member 39 discussed above.
[0146] For example, a durable fabric may be used as an protective
member 92 to promote evaporation and aeration while still
protecting against puncture, snagging, abrasion, wear, and the
like. Meanwhile, other members such as polymeric materials may
minimize access to air, optimize evaporation of fluids, or the
like. Accordingly, the protective member 92 may be designed
according to the functionality desired.
[0147] In certain embodiments, the member 93 may be a stay-dry
(hydrophobic) lining. For example, because a wicking layer 95 will
tend to draw a fluid from a transport wicking layer 94, the wicking
layer 94 may need to be separated by a stay-dry liner 93.
Accordingly, the lining member 93 rejects transport of liquids
therethrough, therein, or both. Liquids preferentially stay in the
wicking layer 94.
[0148] The functions of the members 92 and 93 may be reversed. For
example, a stay-dry material may form the protective member 92. As
a practical matter, the structurally protective member 92 typically
serves best as the outermost member. Accordingly, the protective
member 92, may itself need to be protected against wicking from
liquids being transported in a wicking transport member 94. Thus, a
stay-dry lining member 93 rejects the transport of liquid from the
wicking layer 94 into either of the protective member 92 and the
outside environment.
[0149] A stay-dry lining member 93 resists wicking into the
protective member 92. For example, if a dressing 16 is laden with
liquid fluid, typically saturated, then the fluid may be wicked out
into such items as cotton bed clothes, bedding, and the like.
Accordingly, a stay-dry lining 93 may resist the transport of
liquid out of the transport wicking layer 94. If the protective
member 92 is imperious to liquid, then a stay-dry linen member 93
may not be required.
[0150] On the other hand, where aeration or evaporation is desired,
the protective member 92 may be primarily a mechanical protection,
very porous and susceptible to absorbing liquid from an optional
transport wicking layer 94. The wicking layer 95 is typically
formed of a material having a smaller effective pore size than that
of the protective member 92 or the transport wicking layer 94.
Accordingly, the wicking material 95 preferentially attracts fluids
from the transport wicking layer 94. Thus the wicking layer 95 may
be the principle delivery member for the skin defect. The stay-dry
member 93 may be integral with or one and the same as the
protective member 92 and the protective member 92 may have all the
characteristics and functionality of the stay-dry member 93.
[0151] Having two wicking layers 94, 95 is optional. Either may
suffice. However a smaller pore size promotes delivery independent
from orientation, while larger pore size promotes faster capillary
transport. A member 94 may thus be thought of as a distribution
member. The distribution member 94 may provide a pore size (e.g.
interstitial gap, etc.) having less resistance to flow then the
wicking layer 95. It will be appreciated by those of skill in the
art that the distribution member 94 may also be the distribution
member 40 and/or 68b described above.
[0152] Meanwhile, a non-adhering interface member 96 may cover the
principal wicking layer 95 which may be part of the distribution
member. The interface member 96 may be the same interface member 78
described above. Dimensions of the dressing 16 of FIG. 7 may be
selected as appropriate. For example, the scales or sizes of the
thickness of the non-adhering interface member 96 and the wicking
distribution member 95 are effectively polar opposites. The
non-adhering interface member 96 (if a solid polymer) is typically
as thin as possible and perforated in order to promote transport of
the fluid from the wicking layer 95. If the non-adhering interface
member 96 is a gel, it may diffuse an active ingredient with or
without the carrier to the treated skin defect. A gel may also
largely liquefy or disintegrate (to a greater or lesser extent,
depending on formulation) in the presence of liquids, promoting
direct delivery of a liquid from a wicking layer 95 to skin
defect.
[0153] In one embodiment, the interface member 96 is positioned
between the distribution member 94 and a skin defect being treated
by the dressing 16. The interface member 96 configured to transport
the fluid into contact with the skin defect. The protective member
92 may be positioned adjacent to the distribution member 94. As
discussed above, the protective member 92 may protect the
distribution member 94 from loss of functionality. For example, if
the distribution member 94 is damaged in some way or clogged or if
the structure is altered, the distribution member 94 may not spread
the fluid substantially uniformly. Furthermore, the protective
member 92 may be semi-occlusive and may aid in directing fluid out
of the distribution member 94 and onto the skin defect. Thus, the
protective member 92 might ensure ability of moisture or vapors to
leave the distribution member and to leave the dressing in order to
balance the moisture content of the dressing and thus the fluid
level balance in the skin defect.
[0154] The dressing 16 of FIG. 7 may be configured with any of the
members 92-96 shown, some of them, or additional members, as
desired. Typically, any of the dressings 16 discussed hereinabove
may be made with one or more of the members 92-96 illustrated in
the dressing 16. Accordingly, a multi member dressing 16 may be
engineered to accomplish its functions in the most effective way by
using the appropriate selection of members 92-96. The multi-member
dressing may include a wicking layer receiving the fluid, a barrier
member that may or may not be configured to protect the dressing
from the environment and provide for vapor transmission, a transfer
member to transfer the fluid to the distribution member, an fluid
absorber member to absorb excessive fluid being delivered or for
absorbing the wound exudate, a tenting member positioned at the rim
of the dressing to provide for lateral evaporation, and an
interface member between the wicking layer and the treated skin
defect to transfer the fluid thereto from the wicking layer while
performing any other function needed, such as sealing,
anti-adhesion, or the like. Alternatively, the dressing may
comprise at least one functional member consisting of a
distribution member an interface member, a transport member, a
protective member, and an absorption member. Any of said members
could be integrated to achieve multiple functions in one or more
members. Thus, one or more of the members 92-96 may be structured
to operate as at least one of an interface member, a distribution
member, a fluid transport member, a protective member, a tenting
member, a fluid absorber, and a combination thereof.
[0155] Referring to FIG. 8, a controller 100 may control an
electrochemical reactor 98 producing byproducts 101 or gasses 101.
These byproducts 101a, 101b are generated in response to the
spontaneous flow of electrons and ions in the electrochemical
reactor 98 or galvanic cell 98. The active members 102, 106 may
contribute or consume electrons. Either one may generate a
byproduct 101 that becomes a gas for the reservoir 22 (FIGS. 1 and
2).
[0156] Often, one material 102, 106 may create a byproduct 101 as a
gas, while the other material 106, 102 produces a byproduct that
stays in solution or plates out at a surface of the other active
material 106, 102. A separator 104 may or may not be used
in-between the two active materials. Regardless of the chemistry,
or the mechanism, the electrochemical reactor 98 may be made to
generate a byproduct 101 in a gaseous state by choosing the
chemistry of the electrodes 102, 106 and controlling the electrical
current through a circuit 107.
[0157] In the illustrated embodiment, the electricity generated or
the current generated through the circuit 107 is not the object,
but rather the byproduct gasses that are discharged as a result of
the flow of electrons. However, such a battery or galvanic cell 98
is designed to optimize the generation of the byproduct 101, rather
than optimizing the output of electricity through the circuit
107.
[0158] The circuit 107 may control electron flow, and thus the
generation of gas. In one basic embodiment, a controller 100a may
include a switch 110 to close the circuit 107. To limit the rate of
electrochemical reaction, and thus the generation of gas, some
impedance 108, such as a resistor 108, may be in the circuit 107.
Thus, a controller 100 in a simplest embodiment may simply be a
module 100a or controller 100a providing a physical switch 110 and
an impedance 108. In this embodiment, the switch 110 may
selectively open and close.
[0159] In some embodiments, the switch may operate a single time to
move from an open position to a closed position. In alterative
embodiments, the switch 110 may selectively open again to stop
generation of gas. In a more sophisticated embodiment, a controller
100b may include a control panel 112 having a display 114. A user
may read instructions or bring up menus on the display 114. By
various buttons 115-118 a user may select an "on" or "off"
condition, provide a rate increase or decrease in the production of
gas.
[0160] In general, a controller 100b may be a simple analog or
digital circuit accomplishing certain limited functions. Likewise,
the controller 100b may include additional sophistication.
[0161] For example, in one embodiment, a controller 100c may
actually be a microprocessor-based controller 100c. For example, in
the illustrated embodiment, a central processing unit 120 (CPU 120)
may operably connect to a memory device 122. In a typical
embodiment, the processor 120 may operate controls 124 such as
relays, gates, and the like for increasing current flow from a very
low rate through the circuit 107 to a very high rate.
[0162] In one contemplated embodiment, the processor 120 may
receive instructions, data, or the like, through an input/output
interface 126 (I/O interface). For example, sensors 128 may
operably connect to provide inputs to the I/O interface 126.
Sensors 128 may monitor pressures, humidity, chemical
concentration, electrochemical properties, or the like from the
dressing 16 or elsewhere in the system 10and report through the I/O
interface 126 to the processor 120 to control the device
operation.
[0163] The processor 120 may be programmed with an application 130
stored in a memory device 122. Alternatively, the processor 120 may
execute the application 130 to provide feedback control based on
sensors 128 to control a value of a desired property, parameter, or
condition associated with the dressing 16. For example the pump 12
may be controlled according to humidity sensed by a sensor 128
within the dressing 16. In such an embodiment, for example, a
portion of the dressing 16 may be sensed to determine that the
liquid of a fluid has evaporated or has a certain concentration of
a chemical detected.
[0164] In general, the pump may be as simple or sophisticated as
warranted by cost, medical constraints, or desired controls for
applying a fluid to a dressing 16. In general, any physical
parameter that may be sensed by a sensor 128 may be used to control
the processor 120 through a suitable application 130 programmed to
do so. Accordingly, more gas may be generated by the generator 20,
prompting the flow of additional fluid from the fluid source 26
through the feed conduit 14 and into the dressing 16.
[0165] Typically, the application 130 will operate on top of an
operating system 132 or O/S 132. Other functional features may be
accomplished by other software 134 executed in the processor 120
based on data 134 in memory 122. For example, other data 134 may
include a history of operation of the gas generator 20 by time,
chemical, current, gas volume, or the like. So long as physical
equations are known, they can be programmed into the application
130 to detect and store data 134. Data 134 may also include other
applications such as supporting applications, control applications,
data management applications, and the like.
[0166] Referring to FIG. 9, a cross section of a housing 18 may
include a reservoir 22 storing gas. Likewise, a fluid source 26 may
contact a reservoir 22. Motion or pressure by the reservoir 22 will
result in corresponding motion or pressure in the fluid source 26.
Typically, the fluid source 26 may be pre-filled or filled at point
of use. In the illustrated embodiment, the reservoir 22 and fluid
source 26 may be installed such that initially the gas reservoir 22
occupies very little or comparatively little space. Meanwhile, upon
filling, either at a factory or at point of use, the fluid source
26 typically occupies the majority of the space within the housing
18.
[0167] As gas is generated in the gas reservoir 22, it displaces
space occupied by the fluid source 26, discharging the fluid
through an outlet fitting 32 to a feed conduit 14 and on to a
dressing 16. In the illustrated embodiment, the reservoir 22 and
fluid source 26 may substantially occupy the available space within
the housing 18. The reservoir 22 and fluid source 26 may have
elastomeric properties. However, elastomeric materials may also
react with certain fluids.
[0168] For example, many fluids involve extremely small amounts of
an active ingredient in an overwhelming volume of a carrier.
Meanwhile, an active ingredient may be very reactive. Thus, a trace
amount of a metal or other contaminant may react with a large
amount of an available active ingredient. Thus, the fluid source 26
is better served if made of less reactive materials.
[0169] The fluid source 26 should typically not have any
deleterious effect on the fluid. Likewise, no constituent of the
fluid's active ingredient, carrier, or other excipient should
attack the integrity of the fluid source 26 during its operational
lifetime. Accordingly, materials, sizes, and properties may be
selected to provide an optimum chemical stability, mechanical
integrity, pressure support, and so forth needed for the particular
apparatus 10 and method contemplated.
[0170] In certain embodiments, the reservoir 22 and fluid source 26
may actually have elastic properties (e.g. elastic restrictions,
spring pistons, etc.) and provide some resisting amount of pressure
when inflated. Alternatively, the reservoir 22 and fluid source 26
may have a substantially fixed wall area, capable of enclosing a
fixed maximum volume. Accordingly, as either the reservoir 22 or
the fluid source 26 is filled, it may expand toward its maximum
volume without substantial resistance until that point is
reached.
[0171] Referring to FIG. 10, a reservoir 22 and fluid source 26 may
be formed of laminated or bonded layers of materials. The housing
may be openable or sealed, disposable or re-usable. The reservoir
22 and fluid source 26 need not be limited to a single reservoir
each within the housing 18. Multiple reservoirs 22 may be used or
multiple fluid sources 26. Likewise, reservoir 22 and fluid source
26 may be replaceable, refillable, or both.
[0172] For example, in certain inexpensive embodiments, a very
simple switch 100 may control a gas generator 20 filling a
reservoir 22. The time may be fixed by the chemistry, size, and so
forth of the principle elements 102, 104, 106 of the
electrochemical reactor 98. A second reservoir 22, with a second
gas generator 20 may be useful for operating the apparatus 10 a
second time, after refilling of the fluid source 26. In such a way,
a multi-use, disposable unit may still result with very primitive
controls 100.
[0173] A method for treating a skin defect is also disclosed. The
method includes providing a dressing or fluid delivery system
comprising a feed conduit and a distribution member in fluid
communication with the feed conduit. The distribution member is
configured to receive a fluid and comprising a material to
substantially uniformly distribute the fluid across the
distribution member irrespective of the orientation of the
distribution member. The dressings and delivery systems described
in their various embodiments and combinations in this application
may be used for the dressing or fluid delivery system used in the
method treating a skin defect.
[0174] The method includes applying the dressing to a skin defect
and supplying a fluid to the distribution member through the feed
conduit. Supplying a fluid in one embodiment may include supplying
a pre-determined quantity of fluid containing an active ingredient.
Supplying a fluid may also include priming the dressing with a
quantity of fluid. In another embodiment, priming the dressing with
a quantity of fluid is a separate step. Supplying a fluid may also
include providing a bolus of fluid to the dressing before or after
an initial quantity of fluid is supplied. In one embodiment,
supplying a quantity of fluid is provided manually from a fluid
source to the dressing. In another embodiment, fluid is
automatically provided from a fluid source to the dressing. In
other embodiments, the dressing or system may include a controller
of the type described herein which may be programmed to supply the
fluid at a predetermined flow rate or time interval. The supply of
fluid by any of these methods may be continuous or at intervals
with varying flow rates.
[0175] The method includes the step of distributing the fluid
substantially uniformly across the distribution member. The method
also includes substantially uniformly distributing the fluid to the
skin defect irrespective of the orientation the distribution
member.
[0176] Supplying fluid to the distribution member comprises
maintaining a fluid with a concentration of active ingredient
greater than, equal to, or less than a predetermined threshold over
a predetermined period of time. This may include maintaining the
concentration of the fluid at a minimally therapeutically effective
threshold throughout the distribution member. Supplying a quantity
of fluid to the distribution member may be such that the skin
defect receives a concentration of the active ingredient greater
than a therapeutically effective threshold corresponding to a
minimum inhibitory concentration.
[0177] It will be appreciated by those of skill in the art that it
may be desirous to maintain the concentration of the active
ingredient below a value corresponding to a maximum concentration
above which the active ingredient causes side effects. Furthermore,
a concentration of active ingredient may be selected to
substantially minimize the development of resistance, by a target
organism, to the active ingredient, throughout a pre-selected
period of time. Maintaining a concentration of active ingredient in
the distribution member above, at, or below a threshold, such that
the desired concentration is applied to the skin defect may be
beneficial to facilitate pain or inflammation reduction or to
promote healing of the tissue.
[0178] The method may also include trimming or cutting the dressing
or one or more layers or member that make up the dressing to a
desired shape corresponding to a treatment area.
[0179] The present invention may be embodied in other specific
forms without departing from its spirit or essential
characteristics. The described embodiments are to be considered in
all respects only as illustrative, and not restrictive. The scope
of the invention is, therefore, indicated by the appended claims,
rather than by the foregoing description. All changes which come
within the meaning and range of equivalency of the claims are to be
embraced within their scope.
* * * * *