Molecular sieve abstract
An apparatus for promoting the clotting of blood and controlling
bleeding comprises a receptacle for retaining molecular sieve material
in particulate form therein. A pad for controlling bleeding comprises
a mesh structure and a rigid or semi-rigid support attached to the
mesh structure to facilitate the application of pressure to the
pad and the wound. A bandage applicable to a bleeding wound comprises
a mesh structure and a flexible substrate attached to the mesh structure,
the substrate being a cloth or plastic member that may be adhesively
attached to cover a wound. In any embodiment, at least a portion
of the receptacle or mesh structure is defined by a mesh having
openings therein, and at least a portion of the particulate molecular
sieve material is in direct contact with blood.
Molecular sieve claims
1. An apparatus for promoting the clotting of blood, comprising:
a receptacle for retaining molecular sieve material in particulate
form therein, at least a portion of said receptacle being defined
by a mesh having openings therein; wherein when treating a bleeding
wound, application of said apparatus causes at least a portion of
said particulate molecular sieve material to come into contact with
blood through said openings.
2. The apparatus for promoting the clotting of blood of claim 1
wherein said molecular sieve material is a zeolite.
3. The apparatus for promoting the clotting of blood of claim 2
wherein said zeolite comprises particles having diameters of about
0.2 mm to about 10 mm.
4. The apparatus for promoting the clotting of blood of claim 2
wherein said zeolite comprises particles having diameters of about
1 mm to about 7 mm.
5. The apparatus for promoting the clotting of blood of claim 2
wherein said zeolite comprises particles having diameters of about
2 mm to about 5 mm.
6. The apparatus for promoting the clotting of blood of claim 1
wherein said mesh structure is flexible.
7. The apparatus for promoting the clotting of blood of claim 1
wherein at least one particle of said particulate molecular sieve
material protrudes through one of said openings.
8. A pad for controlling bleeding, said pad comprising: a mesh
structure; particles of molecular sieve material retained in said
mesh structure; and a support attached to said mesh structure; wherein
said mesh structure is defined by openings sized to accommodate
the flow of blood therethrough.
9. The pad of claim 8 wherein said molecular sieve material is
a zeolite.
10. The pad of claim 9 wherein said zeolite comprises particles
having diameters of about 0.2 mm to about 10 mm.
11. The pad of claim 9 wherein said zeolite comprises particles
having diameters of about 1 mm to about 7 mm.
12. The pad of claim 9 wherein said zeolite comprises particles
having diameters of about 2 mm to about 5 mm.
13. The pad of claim 8 wherein said support is configured to have
a pressure applied thereto to enable said pad to be retained on
a bleeding wound.
14. A bandage applicable to a bleeding wound, said bandage comprising:
a substrate; a mesh mounted on said substrate; and particles of
a molecular sieve material retained in said mesh; said mesh defined
by a plurality of members arranged to define openings, said openings
being dimensioned to accommodate the flow of blood therethrough.
15. The bandage of claim 14 further comprising an adhesive on
said substrate, said adhesive being configured to facilitate the
retaining of said bandage on the skin of a wearer.
16. The bandage of claim 14 wherein said substrate includes holes.
17. The bandage of claim 14 wherein said molecular sieve material
is a zeolite.
18. A method of dressing a bleeding wound, said method comprising
the steps of: providing a molecular sieve material in particle form
and retained in a mesh structure; placing said mesh structure on
a bleeding wound such that said molecular sieve material contacts
wounded tissue of said bleeding wound; applying pressure to said
mesh structure; and removing said mesh structure from said wound.
19. The method of claim 18 further comprising the step of holding
said mesh structure on said bleeding wound using a strapping device.
Molecular sieve description
TECHNICAL FIELD
[0001] The present invention relates generally to blood clotting
devices and, more particularly, to blood clotting materials, devices
incorporating such materials, and methods for the delivery of such
materials for use as bleeding control devices.
BACKGROUND OF THE INVENTION
[0002] Blood is a liquid tissue that includes red cells, white
cells, corpuscles, and platelets dispersed in a liquid phase. The
liquid phase is plasma, which includes acids, lipids, solublized
electrolytes, and proteins. The proteins are suspended in the liquid
phase and can be separated out of the liquid phase by any of a variety
of methods such as filtration, centrifugation, electrophoresis,
and immunochemical techniques. One particular protein suspended
in the liquid phase is fibrinogen. When bleeding occurs, the fibrinogen
reacts with water and thrombin (an enzyme) to form fibrin, which
is insoluble in blood and polymerizes to form clots.
[0003] In a wide variety of circumstances, animals, including humans,
can be wounded. Often bleeding is associated with such wounds. In
some circumstances, the wound and the bleeding are minor, and normal
blood clotting functions in addition to the application of simple
first aid are all that is required. Unfortunately, however, in other
circumstances substantial bleeding can occur. These situations usually
require specialized equipment and materials as well as personnel
trained to administer appropriate aid. If such aid is not readily
available, excessive blood loss can occur. When bleeding is severe,
sometimes the immediate availability of equipment and trained personnel
is still insufficient to stanch the flow of blood in a timely manner.
[0004] Moreover, severe wounds can often be inflicted in remote
areas or in situations, such as on a battlefield, where adequate
medical assistance is not immediately available. In these instances,
it is important to stop bleeding, even in less severe wounds, long
enough to allow the injured person or animal to receive medical
attention.
[0005] In an effort to address the above-described problems, materials
have been developed for controlling excessive bleeding in situations
where conventional aid is unavailable or less than optimally effective.
Although these materials have been shown to be somewhat successful,
they are sometimes not effective enough for traumatic wounds and
tend to be expensive. Furthermore, these materials are sometimes
ineffective in some situations and can be difficult to apply as
well as remove from a wound.
[0006] Additionally, or alternatively, the previously developed
materials can produce undesirable side effects. For example, prior
art blood clotting material is generally a powder or a fine particulate
in which the surface area of the material often produces an exothermic
reaction upon the application of the material to blood. Oftentimes
excess material is unnecessarily poured onto a wound, which can
exacerbate the exothermic effects. Depending upon the specific attributes
of the material, the resulting exothermia may be sufficient to cause
discomfort to or even burn the patient. Although some prior art
patents specifically recite the resulting exothermia as being a
desirable feature that can provide clotting effects to the wound
that are similar to cauterization, there exists the possibility
that the tissue at and around the wound site may be undesirably
impacted.
[0007] Furthermore, to remove such materials from wounds, irrigation
of the wound is often required. If an amount of material is administered
that causes discomfort or burning, the wound may require immediate
flushing. In instances where a wounded person or animal has not
yet been transported to a facility capable of providing the needed
irrigation, undesirable effects or over-treatment of the wound may
result.
[0008] Bleeding can also be a problem during surgical procedures.
Apart from suturing or stapling an incision or internally bleeding
area, bleeding is often controlled using a sponge or other material
used to exert pressure against the bleed site and/or absorb the
blood. However, when the bleeding becomes excessive, these measures
may not be sufficient to stop the flow of blood. Moreover, any highly
exothermic bleed-control material may damage the tissue surrounding
the bleed site and may not be configured for easy removal after
use.
[0009] Based on the foregoing, it is a general object of the present
invention to provide devices for controlling bleeding and methods
of their use that overcome or improve upon the prior art.
SUMMARY OF THE INVENTION
[0010] According to one aspect, the present invention resides in
an apparatus for promoting the clotting of blood, thereby controlling
bleeding. The apparatus comprises a receptacle for retaining molecular
sieve material in particulate form therein. At least a portion of
the receptacle is defined by a mesh having openings therein such
that when the apparatus is applied to a bleed site, the particulate
molecular sieve material comes into contact with blood through the
openings.
[0011] Other aspects of the present invention include a pad for
controlling bleeding and a bandage applicable to a bleeding wound.
In both the pad and the bandage, there is a mesh structure and particles
of molecular sieve material retained therein. In the pad embodiment,
there is a rigid or semi-rigid support attached to the mesh structure
to facilitate the application of pressure to the pad and the wound.
In the bandage, there is a flexible substrate attached to the mesh
structure, the substrate being a cloth or plastic member that may
be adhesively attached to cover a wound. In any embodiment, the
mesh structure may be defined by a plurality of members (strands,
filaments, or strips of synthetic or natural material) interconnected
and arranged to define openings. The openings are sized to allow
contact to be maintained between the particles of the molecular
sieve material and blood.
[0012] In yet another aspect of the present invention, a method
of dressing a bleeding wound includes providing a molecular sieve
material in particle form and retaining the material in a mesh structure,
placing the mesh structure on a bleeding wound such that the molecular
sieve material comes into contact with blood flowing from the wound,
applying pressure to the mesh structure to ensure contact of the
material with the blood, and removing the mesh structure from the
wound.
[0013] An advantage of the present invention is that upon completion
of the application of any of the devices of the present invention
to a bleeding wound, the devices can be easily removed. In particular,
because the zeolite material is in granule, bead, or pellet form
and encased in a pouch or mesh structure, the material can be cleanly
pulled away from the treated wound and disposed of. Accordingly,
little or no irrigation of the wound is required to flush away remaining
zeolite. In devices in which the pouch containing zeolite material
is incorporated into an adhesive bandage, the device can be left
on the wound for the amount of time necessary to cause clotting.
[0014] Another advantage is that the particlized form of the zeolite
material allows the material to react less exothermically with blood.
As the particle size increases (e.g., from fine to coarse), the
surface area of the particles that the blood can come into contact
with decreases. The porous nature of the material still allows liquid
blood constituents to be wicked away to cause thickening of the
blood, thereby facilitating the formation of clots. Because the
particle surface area exposed to the blood is reduced, a less aggressive
drawing of moisture from the blood is realized, which thereby tempers
the exothermic effects experienced at the wound site.
[0015] Still another advantage of the present invention is that
the proper dose of molecular sieve material can be readily applied
to an open wound. Particularly when the device is a porous pouch
containing zeolite material, the device can be readily removed from
sterilized packaging and held directly at the points from which
blood emanates to facilitate clotting of the blood without spilling
powder or pellets outside the wound area. Guesswork, estimation,
or calculation of the amounts of molecular sieve material for application
to a bleeding wound is eliminated. Accordingly, little or no molecular
sieve material is wasted.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is a schematic representation of a blood clotting
device of the present invention.
[0017] FIG. 2 is a side view of the blood clotting device of FIG.
1 illustrating the retaining of molecular sieve particles in a mesh
container.
[0018] FIG. 3 is a side view of a pressure pad incorporating the
molecular sieve particles encapsulated in a mesh container for pressure
application to a bleeding wound.
[0019] FIG. 4 is a perspective view of a bandage incorporating
the molecular sieve particles in a mesh container for application
to a bleeding wound.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0020] Disclosed herein are devices and methods for delivering
materials to wounds to promote the clotting of blood and the dressing
of the wounds. The devices generally comprise expedients or apparatuses
that can be applied to bleeding wounds such that the materials contact
the tissue of the wound to minimize or stop a flow of blood by absorbing
at least portions of the liquid phases of the blood, thereby promoting
clotting. One apparatus comprises a receptacle for retaining molecular
sieve material in particulate form therein. At least a portion of
the receptacle is defined by a mesh having openings therein, and
at least a portion of the particulate molecular sieve material is
in direct contact with blood through the openings.
[0021] The molecular sieve material used in the present invention
may be a synthetic polymer gel, cellulosic material, porous silica
gel, porous glass, alumina, hydroxyapatite, calcium silicate, zirconia,
zeolite, or the like. Exemplary synthetic polymers include, but
are not limited to, stylene-divinylbenzene copolymer, cross-linked
polyvinyl alcohol, cross-linked polyacrylate, cross-linked vinyl
ether-maleic anhydride copolymer, cross-linked stylene-maleic anhydride
copolymer or cross-linked polyamide, and combinations thereof.
[0022] The molecular sieve material is preferably a zeolite. Other
molecular sieve materials that may be used include, but are not
limited to, faujasite. As used herein, the term "zeolite"
refers to a crystalline form of aluminosilicate having the ability
to be dehydrated without experiencing significant changes in the
crystalline structure. The zeolite may include one or more ionic
species such as, for example, calcium and sodium moieties. Typically,
the zeolite is a friable material that is about 90% by weight calcium
and about 10% by weight sodium. The calcium portion contains crystals
that are about 5 angstroms in size, and the sodium portion contains
crystals that are about 4 angstroms in size. The preferred molecular
structure of the zeolite is an "A-type" crystal, namely,
one having a cubic crystalline structure that defines round or substantially
round openings.
[0023] The zeolite may be mixed with or otherwise used in conjunction
with other materials having the ability to be dehydrated without
significant changes in crystalline structure. Such materials include,
but are not limited to, magnesium sulfate, sodium metaphosphate,
calcium chloride, dextrin, a polysaccharide, combinations of the
foregoing materials, and hydrates of the foregoing materials.
[0024] Zeolites for use in the disclosed applications may be naturally
occurring or synthetically produced. Numerous varieties of naturally
occurring zeolites are found as deposits in sedimentary environments
as well as in other places. Naturally occurring zeolites that may
be applicable to the compositions described herein include, but
are not limited to, analcite, chabazite, heulandite, natrolite,
stilbite, and thomosonite. Synthetically produced zeolites that
may also find use in the compositions and methods described herein
are generally produced by processes in which rare earth oxides are
substituted by silicates, alumina, or alumina in combination with
alkali or alkaline earth metal oxides.
[0025] Various materials may be mixed with, associated with, or
incorporated into the zeolites to maintain an antiseptic environment
at the wound site or to provide functions that are supplemental
to the clotting functions of the zeolites. Exemplary materials that
can be used include, but are not limited to, pharmaceutically-active
compositions such as antibiotics, antifungal agents, antimicrobial
agents, anti-inflammatory agents, analgesics (e.g., cimetidine,
chloropheniramine maleate, diphenhydramine hydrochloride, and promethazine
hydrochloride), bacteriostatics, compounds containing silver ions,
and the like. Other materials that can be incorporated to provide
additional hemostatic functions include ascorbic acid, tranexamic
acid, rutin, and thrombin. Botanical agents having desirable effects
on the wound site may also be added.
[0026] In one embodiment of the present invention, a device for
facilitating the clotting of blood directly at a wound site is shown
with reference to FIG. 1. The device is a permeable pouch that allows
liquid to enter to contact blood clotting zeolite (or other molecular
sieve) material retained therein. Sealed packaging (not shown) provides
a sterile environment for storing the device until it can be used.
The device, which is shown generally at 10 and is hereinafter referred
to as "pouch 10" comprises a screen or mesh 12 and zeolite
particles 14 retained therein by the screen or mesh. The mesh 12
is closed on all sides and defines openings that are capable of
retaining the zeolite particles 14 therein while allowing liquid
to flow through. As illustrated, the mesh 12 is shown as being flattened
out, and only a few zeolite particles 14 are shown.
[0027] The zeolite particles 14 are substantially spherical or
irregular in shape (e.g., balls, beads, pellets, or the like) and
about 0.2 millimeters (mm) to about 10 mm in diameter, preferably
about 1 mm to about 7 mm in diameter, and more preferably about
2 mm to about 5 mm in diameter. In any embodiment (balls, beads,
pellets, etc.), less particle surface area is available to be contacted
by blood as the particle size is increased. Therefore, the rate
of clotting can be controlled by varying the particle size. Furthermore,
the adsorption of moisture (which also has an effect on the exothermic
effects of the zeolite) can also be controlled.
[0028] The mesh 12 is defined by interconnected strands, filaments,
or strips of material. The strands, filaments, or strips can be
interconnected in any one or a combination of manners including,
but not limited to, being woven into a gauze, intertwined, integrally-formed,
and the like. Preferably, the interconnection is such that the mesh
can flex while substantially maintaining the dimensions of the openings
defined thereby. The material from which the strands, filaments
or strips are fabricated may be a polymer (e.g., nylon, polyethylene,
polypropylene, polyester, or the like), metal, fiberglass, or an
organic substance (e.g., cotton, wool, silk, or the like).
[0029] Referring now to FIG. 2 the openings defined by the mesh
12 are dimensioned to retain the zeolite particles 14 but to accommodate
the flow of blood therethrough. Because the mesh 12 may be pulled
tight around the zeolite particles 14 the particles may extend
through the openings by a distance d. If the zeolite particles 14
extend through the openings, the particles are able to directly
contact tissue to which the pouch 10 is applied. Thus, blood emanating
from the tissue immediately contacts the zeolite particles 14 and
the water phase thereof is wicked into the zeolite material, thereby
facilitating the clotting of the blood. However, it is not a requirement
of the present invention that the zeolite particles protrude through
the mesh.
[0030] To apply the pouch 10 to a bleeding wound, the pouch is
removed from the packaging and placed on the bleeding wound. The
zeolite particles 14 in the mesh 12 contact the tissue of the wound
and/or the blood, and at least a portion of the liquid phase of
the blood is adsorbed by the zeolite material, thereby promoting
the clotting of the blood.
[0031] Another embodiment of the present invention is a pad which
is shown at 20 with reference to FIG. 3 and is hereinafter referred
to as "pad 20." The pad 20 comprises the mesh 12 zeolite
(or other molecular sieve) particles 14 retained therein by the
mesh 12 and a support 22 to which pressure may be applied in the
application of the pad 20 to a bleeding wound. The mesh 12 as above,
has openings that are capable of retaining the zeolite particles
14 therein while allowing the flow of blood therethrough.
[0032] The mesh 12 is stitched, glued, clamped, or otherwise mounted
to the support 22. The support 22 comprises an undersurface 24 against
which the zeolite particles 14 are held by the container 12 and
a top surface 26. The undersurface 24 is impermeable to the zeolite
particles 14 (migration of the particles into the support 22 is
prevented) and is further resistant to the absorption of water or
other fluids. The top surface 26 is capable of having a pressure
exerted thereon by a person applying the pad 20 to a bleeding wound
or by a weight supported on the top surface 26. The entire support
22 is rigid or semi-rigid so as to allow the application of pressure
while minimizing discomfort to the patient.
[0033] To apply the pad 20 to a bleeding wound, the pad 20 is removed
from its packaging and placed on the bleeding wound. As with the
pouch of the embodiment of FIGS. 1 and 2 the zeolite particles
14 are either in direct contact with the tissue of the wound or
are in direct contact with the blood. Pressure may be applied to
the wound by pressing on the top surface 26 with a hand or by placing
a weight on the surface, thereby facilitating the contact between
the zeolite particles 14 and the wound and promoting the adsorption
of the liquid phase of the blood. The pad 20 (with or without a
weight) may also be held onto the wound using a strapping device
such as a belt, an elastic device, hook-and-loop material, combinations
of the foregoing devices and materials, and the like.
[0034] Referring now to FIG. 4 another embodiment of the present
invention is a bandage, shown at 50 which comprises zeolite particles
14 (or some other molecular sieve material) retained in a mesh 12
and mounted to a flexible substrate 52 that can be applied to a
wound (for example, using a pressure-sensitive adhesive to adhere
the bandage 50 to the skin of a wearer). The mesh 12 is stitched,
glued, or otherwise mounted to a substrate 52 to form the bandage
50.
[0035] The substrate 52 is a plastic or a cloth member that is
conducive to being retained on the skin of an injured person or
animal on or proximate a bleeding wound. An adhesive 54 is disposed
on a surface of the substrate 52 that engages the skin of the injured
person or animal. Particularly if the substrate 52 is a non-breathable
plastic material, the substrate may include holes 56 to allow for
the dissipation of moisture evaporating from the skin surface.
[0036] In the preparation of zeolite material for the devices of
the present invention (i.e., formation of the material into particle
form), an initial level of hydration of the zeolite may be controlled
by the application of heat to the zeolite material either before
or after the material is formed into particles. However, it has
also surprisingly been found that as the particle size of the zeolite
is increased, the moisture content has less of a correlative effect
on any exothermia produced as the result of mixing the particlized
zeolite in blood. As such, formation of the zeolite material into
the zeolite particles (shown at 14 in FIGS. 1-4), may be by extrusion,
milling, casting, or the like.
[0037] Although this invention has been shown and described with
respect to the detailed embodiments thereof, it will be understood
by those of skill in the art that various changes may be made and
equivalents may be substituted for elements thereof without departing
from the scope of the invention. In addition, modifications may
be made to adapt a particular situation or material to the teachings
of the invention without departing from the essential scope thereof.
Therefore, it is intended that the invention not be limited to the
particular embodiments disclosed in the above detailed description,
but that the invention will include all embodiments falling within
the scope of the appended claims. |