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Publication numberUS20070134293 A1
Publication typeApplication
Application numberUS 11/634,673
Publication dateJun 14, 2007
Filing dateDec 5, 2006
Priority dateFeb 9, 2005
Also published asCA2597243A1, CA2597243C, CN101141984A, DE602005012225D1, EP1690553A1, EP1690553B1, US8252318, US8257731, US8512743, US8557278, US20060178609, US20070065491, US20100121244, US20120323156, US20130041332, WO2006086557A2, WO2006086557A3, WO2006086557B1
Publication number11634673, 634673, US 2007/0134293 A1, US 2007/134293 A1, US 20070134293 A1, US 20070134293A1, US 2007134293 A1, US 2007134293A1, US-A1-20070134293, US-A1-2007134293, US2007/0134293A1, US2007/134293A1, US20070134293 A1, US20070134293A1, US2007134293 A1, US2007134293A1
InventorsRaymond Huey, Jeffrey Horn, Denny Lo
Original AssigneeHuey Raymond J, Horn Jeffrey L, Denny Lo
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Devices and methods for the delivery of blood clotting materials to bleeding wounds
US 20070134293 A1
Abstract
An apparatus for promoting the clotting of blood comprises a receptacle, at least a portion of which is defined by a mesh having openings therein, and particles of clay retained in the receptacle. In similar apparatuses, bioactive glass or chitosan is retained in the receptacle. An apparatus also comprises a receptacle defined by a mesh having openings therein, and first and second blood clotting materials enclosed in the mesh. In a method of dressing a bleeding wound, a first blood clotting material in particle form is provided and retained in a mesh structure, and a second blood clotting material is provided and incorporated into a material of the mesh structure. The mesh structure is placed on a bleeding wound such that the second blood clotting material contacts wounded tissue of the bleeding wound.
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Claims(31)
1. An apparatus for promoting the clotting of blood, comprising:
a receptacle, at least a portion of said receptacle being defined by a mesh having openings therein; and
a clay in particulate form retained in said receptacle, said clay providing a blood clotting function;
wherein when treating a bleeding wound, application of said apparatus causes at least a portion of said clay to come into contact with blood through said openings.
2. The apparatus for promoting the clotting of blood of claim 1, wherein said clay is selected from the group consisting of attapulgite, bentonite, kaolin, kaolinite, and combinations of the foregoing.
3. The apparatus for promoting the clotting of blood of claim 1, wherein said clay is Edgar's plastic kaolin.
4. The apparatus for promoting the clotting of blood of claim 1, wherein said mesh is flexible.
5. The apparatus for promoting the clotting of blood of claim 1, wherein a material of said mesh defines a matrix in which clay material is captured.
6. The apparatus for promoting the clotting of blood of claim 1, wherein a material of said mesh includes clay material.
7. The apparatus for promoting the clotting of blood of claim 1, wherein a material of said mesh includes bioactive glass.
8. The apparatus for promoting the clotting of blood of claim 1, wherein a material of said mesh includes chitosan.
9. The apparatus for promoting the clotting of blood of claim 1, wherein a material of said mesh includes a material selected from the group consisting of poly-N-acetylglucosamine (derived from algae), thrombin, fibrin, microporous polymer particles, microporous polysaccharide particles, gelatin sponge, microfibrillar collagen, oxidized cellulose, zeolite, and combinations of the foregoing.
10. The apparatus for promoting the clotting of blood of claim 1, wherein a material from which said mesh is fabricated is selected from the group consisting of polymers, metals, fiberglass, organic substances, oxidized cellulose, and cellulose-based materials.
11. The apparatus for promoting the clotting of blood of claim 1, wherein said clay further comprises a material selected from the group consisting of antibiotics, antibacterial agents, antifungal agents, antimicrobial agents, anti-inflammatory agents, analgesics, antihistamines, bacteriostatics, compounds containing silver ions, wound healing agents, ascorbic acid, tranexamic acid, rutin, thrombin, botanical agents, and combinations of the foregoing materials.
12. An apparatus for promoting the clotting of blood, comprising:
a receptacle, at least a portion of said receptacle being defined by a mesh having openings therein; and
a bioactive glass in particulate form retained in said receptacle, said bioactive glass providing a blood clotting function;
wherein when treating a bleeding wound, application of said apparatus causes at least a portion of said bioactive glass to come into contact with blood through said openings.
13. The apparatus for promoting the clotting of blood of claim 12, wherein a material of said mesh includes clay material.
14. The apparatus for promoting the clotting of blood of claim 12, wherein a material of said mesh includes bioactive glass.
15. The apparatus for promoting the clotting of blood of claim 12, wherein a material of said mesh includes chitosan.
16. The apparatus for promoting the clotting of blood of claim 12, wherein a material of said mesh includes a material selected from the group consisting of poly-N-acetylglucosamine (derived from algae), thrombin, fibrin, microporous polymer particles, microporous polysaccharide particles, gelatin sponge, microfibrillar collagen, oxidized cellulose, zeolite, and combinations of the foregoing.
17. The apparatus for promoting the clotting of blood of claim 12, wherein said bioactive glass further comprises a material selected from the group consisting of antibiotics, antibacterial agents, antifungal agents, antimicrobial agents, anti-inflammatory agents, analgesics, antihistamines, bacteriostatics, compounds containing silver ions, wound healing agents, ascorbic acid, tranexamic acid, rutin, thrombin, botanical agents, and combinations of the foregoing materials.
18. An apparatus for promoting the clotting of blood, comprising:
a receptacle, at least a portion of said receptacle being defined by a mesh having openings therein; and
chitosan in particulate form retained in said receptacle, said chitosan providing a blood clotting function;
wherein when treating a bleeding wound, application of said apparatus causes at least a portion of said chitosan to come into contact with blood through said openings.
19. The apparatus for promoting the clotting of blood of claim 18, wherein a material of said mesh includes clay material.
20. The apparatus for promoting the clotting of blood of claim 18, wherein a material of said mesh includes bioactive glass.
21. The apparatus for promoting the clotting of blood of claim 18, wherein a material of said mesh includes chitosan.
22. The apparatus for promoting the clotting of blood of claim 18, wherein a material of said mesh includes a material selected from the group consisting of poly-N-acetylglucosamine (derived from algae), thrombin, fibrin, microporous polymer particles, microporous polysaccharide particles, gelatin sponge, microfibrillar collagen, oxidized cellulose, zeolite, and combinations of the foregoing.
23. The apparatus for promoting the clotting of blood of claim 18, wherein said chitosan further comprises a material selected from the group consisting of antibiotics, antibacterial agents, antifungal agents, antimicrobial agents, anti-inflammatory agents, analgesics, antihistamines, bacteriostatics, compounds containing silver ions, wound healing agents, ascorbic acid, tranexamic acid, rutin, thrombin, botanical agents, and combinations of the foregoing materials.
24. An apparatus for promoting the clotting of blood, comprising:
a receptacle defined by a mesh having openings therein;
a first blood clotting material enclosed in said mesh; and
a second blood clotting material incorporated into a material of said mesh, said second blood clotting material being selected from the group consisting of clay, bioactive glass, chitosan, and combinations of the foregoing;
wherein when treating a bleeding wound, application of said apparatus causes at least a portion of said second blood clotting material to come into contact with blood.
25. The apparatus for promoting the clotting of blood of claim 24, wherein said first blood clotting material is selected from the group consisting of zeolite, oxidized cellulose, clay, bioactive glass, chitosan, and combinations of the foregoing.
26. The apparatus for promoting the clotting of blood of claim 25, wherein said first blood clotting material further comprises a material selected from the group consisting of antibiotics, antibacterial agents, antifungal agents, antimicrobial agents, anti-inflammatory agents, analgesics, antihistamines, bacteriostatics, compounds containing silver ions, wound healing agents, ascorbic acid, tranexamic acid, rutin, thrombin, botanical agents, and combinations of the foregoing materials.
27. The apparatus of claim 24, wherein said first blood clotting material is in particle form.
28. The apparatus of claim 24, further comprising a substrate on which said receptacle is mounted.
29. The apparatus of claim 28, further comprising an adhesive disposed on said substrate to form an adhesive bandage.
30. A method of dressing a bleeding wound, said method comprising the steps of:
providing a first blood clotting material in particle form and retained in a mesh structure;
providing a second blood clotting material incorporated into a material of said mesh structure;
placing said mesh structure on a bleeding wound such that said second blood clotting material contacts wounded tissue of said bleeding wound;
applying pressure to said mesh structure; and
removing said mesh structure from said wound.
31. The method of claim 30, further comprising the step of holding said mesh structure on said bleeding wound using a strapping device.
Description
CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part application of U.S. patent application Ser. No. 11/054,918, filed Feb. 9, 2005, the contents of which are incorporated herein by reference in their entirety.

TECHNICAL FIELD

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

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.

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.

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.

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.

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.

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.

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.

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

According to one aspect, the present invention resides in an apparatus for promoting the clotting of blood. This apparatus comprises a receptacle, at least a portion of which defined by a mesh having openings therein, and a clay in particulate form retained in the receptacle. The clay provides a blood clotting function such that when treating a bleeding wound, application of the apparatus causes at least a portion of the clay to come into contact with blood through the openings of the mesh. In another aspect, the present invention resides in a similar apparatus in which bioactive glass is retained in the receptacle. In still another aspect, the present invention resides in a similar apparatus in which chitosan is retained in the receptacle.

According to another aspect, the present invention resides in an apparatus for promoting the clotting of blood. This apparatus comprises a receptacle defined by a mesh having openings therein; a first blood clotting material enclosed in the mesh; and a second blood clotting material included in a material of the mesh. The second blood clotting material may be a clay, bioactive glass, chitosan, or a combination of the foregoing. When treating a bleeding wound, application of the apparatus causes at least a portion of the second blood clotting material to come into contact with blood.

According to another aspect, the present invention resides in a method of dressing a bleeding wound. In the method, a first blood clotting material in particle form is provided and retained in a mesh structure, and a second blood clotting material is provided and incorporated into a material of the mesh structure. The mesh structure is placed on a bleeding wound such that the second blood clotting material contacts wounded tissue of the bleeding wound. Pressure may be applied to the mesh structure.

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 blood clotting material is clay, bioactive glass, or chitosan 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 blood clotting material.

Another advantage is that the clay, bioactive glass, or chitosan produces little or no exothermic reaction with blood. The physical structures of each type of blood clotting agent still allow liquid blood constituents to be wicked away to cause thickening of the blood, thereby facilitating the formation of clots.

With regard to embodiments in which clay, bioactive glass, chitosan, or other materials are included in the mesh, one advantage is that the contacting surface area between blood clotting agent and the tissue of the wound site is increased. In particular, the flow of blood to the mesh results in immediate clotting effects because a time delay due to the blood having to flow around the mesh material to the blood clotting material is avoided.

Still another advantage of the present invention is that the proper dose of blood clotting material can be readily applied to an open wound. Particularly when the device is a porous pouch containing clay, bioactive glass, or chitosan, 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 blood clotting material for application to a bleeding wound is eliminated. Accordingly, little or no blood clotting material is wasted.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic representation of a blood clotting device of the present invention.

FIG. 2 is a side view of the blood clotting device of FIG. 1 illustrating the retaining of blood clotting particles in a mesh container.

FIG. 3 is a side view of a pressure pad incorporating the blood clotting particles encapsulated in a mesh container for pressure application to a bleeding wound.

FIG. 4 is a perspective view of a bandage incorporating the blood clotting particles in a mesh container for application to a bleeding wound.

FIG. 5 is a side view of a blood clotting device incorporating blood clotting particles retained in a mesh impregnated with clay particles.

FIG. 6 is a side view of one embodiment of the mesh of the device of FIG. 5.

FIG. 7 is a side view of another embodiment of the mesh of the device of FIG. 5.

FIG. 8 is a side view of another embodiment of the mesh of the device of FIG. 5. FIG. 9 is a side view of a bandage incorporating blood clotting particles retained in a clay-impregnated mesh material.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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 blood flow 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, oxidized cellulose material in particulate form, particles of layered clay, bioactive glasses, chitosan, and the like, as well as combinations of the foregoing. 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, oxidized cellulose material, clay, bioactive glass, or chitosan is in direct contact with blood through the openings. As used herein, the terms “particle” and “particulate” are intended to refer to balls, beads, pellets, rods, granules, polymorphous shapes, and combinations of the foregoing.

In embodiments incorporating a molecular sieve material as the blood clotting material, 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.

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.

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.

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.

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, antibacterial agents, antifungal agents, antimicrobial agents, anti-inflammatory agents, analgesics, antihistamines (e.g., cimetidine, chloropheniramine maleate, diphenhydramine hydrochloride, and promethazine hydrochloride), bacteriostatics, compounds containing silver ions, wound healing agents, 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.

In embodiments incorporating oxidized cellulose as the blood clotting material, the oxidized cellulose used in the present invention is a chemically oxidized form of a common cellulose fiber such as cotton and is also known as cellulosic acid, absorbable cellulose, or polyanhydroglucuronic acid. The degree of oxidation of the fiber is a function of the carboxylation content of the fibrous cellulose material. In particular, as the number of carboxyl groups on the cellulose structure is increased, the oxidation content correspondingly increases. Oxidized cellulose may be manufactured by the action of nitrogen dioxide gas (NO2) on cellulose fiber. Other methods of manufacturing oxidized cellulose include oxidation of cellulose fiber with aqueous oxidizing agents such as hypochlorite salts, although the use of such agents is less preferred than the use of nitrogen dioxide gas.

In embodiments incorporating clay as the blood clotting material, the clay may be attapulgite, bentonite, kaolin, kaolinite, or the like, as well as combinations of the foregoing. The present invention is not limited in this regard, however, as other types of clays may be used. Although the term“kaolin” is used hereinafter to describe the present invention, it should be understood that kaolinite may also be used in conjunction with or in place of kaolin.

As used herein, the term“clay” refers to a crystalline form of hydrated aluminum silicate. The crystals of clay are irregularly shaped and insoluble in water. The combination of some types of clay with water may produce a mass having some degree of plasticity. Depending upon the type of clay, the combination thereof with water may produce a colloidal gel having thixotropic properties.

As used herein, the term“kaolin” refers to a soft, earthy aluminosilicate clay (and, more specifically, to a dioctahedral phyllosilicate clay) having the chemical formula Al2Si2O5(OH)4. Kaolin is a naturally occurring layered silicate mineral having alternating tetrahedral sheets and octahedral sheets of alumina octahedra linked via the oxygen atoms of hydroxyl groups. Kaolin comprises about 50% alumina, about 50% silica, and trace impurities.

More preferably, the clay is Edgar's plastic kaolin (hereinafter“EPK”), which is a water-washed kaolin clay that is mined and processed in and near Edgar, Fla. Edgar's plastic kaolin has desirable plasticity characteristics, is castable, and when mixed with water produces a thixotropic slurry.

The kaolin material of the present invention may be mixed with or otherwise used in conjunction with other materials to provide additional clotting functions and/or improved efficacy. Such materials include, but are not limited to, magnesium sulfate, sodium metaphosphate, calcium chloride, dextrin, combinations of the foregoing materials, and hydrates of the foregoing materials.

As with the zeolites, various materials may be mixed with, associated with, or incorporated into the clay to maintain an antiseptic environment at the wound site or to provide functions that are supplemental to the clotting functions of the clay. Exemplary materials that can be used include, but are not limited to, pharmaceutically-active compositions such as antibiotics, antibacterial agents, antifungal agents, antimicrobial agents, anti-inflammatory agents, analgesics, antihistamines (e.g., cimetidine, chloropheniramine maleate, diphenhydramine hydrochloride, and promethazine hydrochloride), bacteriostatics, compounds containing silver ions, wound healing agents, 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.

For use in the present invention, the kaolin (or other clay material) is preferably in particle form. As used herein,“particles” include beads, pellets, granules, rods, or any other surface morphology or combination of surface morphologies. Irrespective of the surface morphology, the particles are about 0.2 mm (millimeters) to about 10 mm, preferably about 0.5 mm to about 5 mm, and more preferably about 1 mm to about 2 mm in effective diameter.

The clay particles can be produced by any of several various methods. Such methods include mixing, extrusion, spheronizing, and the like. Equipment that can be utilized for the mixing, extruding, or spheronizing of the clay is available from Caleva Process Solutions Ltd. in Dorset, United Kingdom. Other methods include the use of a fluid bed or a pelletizing apparatus. Fluid beds for the production of clay particles are available from Glatt Air Technologies in Ramsey, N.J. Disk pelletizers for the production of clay particles are available from Feeco International, Inc., in Green Bay, Wis. Preferably, the clay is extruded through a suitable pelletizing device. The present invention is not limited in this regard, however, as other devices and methods for producing particlized clay are within the scope of the present invention.

The EPK used in the present invention is particlized, dried, and fired to about 600 degrees C. In order to achieve a suitably homogenous mixture of the EPK to form the particles, a relatively high shear is applied to a mass of the EPK using a suitable mixing apparatus. Prior to shearing, the water content of the clay is measured and adjusted to be about 20% by weight to give a sufficiently workable mixture for extrusion and subsequent handling.

During the firing of the EPK to about 600 degrees C, the material is vitrified. Vitrification is effected via repeated melting and cooling cycles to allow the EPK (or other clay material) to be converted into a glassy substance. With increasing numbers of cycles, the crystalline structure is broken down to result in an amorphous composition. The amorphous nature of the EPK allows it to maintain its structural integrity when subsequently wetted. As a result, the EPK maintains its structural integrity when wetted during use, for example, when applied to blood. The present invention is not limited to the use of vitrified clays, however, as clay material that has not been vitrified is still within the scope of the present invention. In particular, unvitrified clay can still be applied to a bleeding wound to provide hemostasis.

It is believed that the cellular clotting mechanism of clay activates certain contact factors when applied to blood. More specifically, it is believed that kaolin (particularly EPK) initiates mechanisms by which water in blood is absorbed to facilitate clotting functions.

In some embodiments, bioactive glass is used as the blood clotting agent. Bioactive glass is a biocompatible surface-reactive glass-ceramic material comprising silicon dioxide and calcium oxide. Some formulations of bioactive glass may include sodium oxide and diphosphorous pentoxide. The glass-ceramic materials that comprise bioactive glasses are formed as traditional glassy materials (amorphous structure), then they are made to crystallize partly by heat treatment. The bioactive glasses are formed as particles, the particles being about 0.2 mm to about 10 mm, preferably about 0.5 mm to about 5 mm, and more preferably about 1 mm to about 2 mm in effective diameter. The particles may be produced by any suitable process.

As with the zeolites and clays, various materials may be mixed with, associated with, or incorporated into the bioactive glass to maintain an antiseptic environment at the wound site or to provide functions that are supplemental to the clotting functions of the bioactive glass. Exemplary materials that can be used include, but are not limited to, pharmaceutically-active compositions such as antibiotics, antibacterial agents, antifungal agents, antimicrobial agents, anti-inflammatory agents, analgesics, antihistamines (e.g., cimetidine, chloropheniramine maleate, diphenhydramine hydrochloride, and promethazine hydrochloride), bacteriostatics, compounds containing silver ions, wound healing agents, 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.

In some embodiments, chitosan may also be used as the blood clotting agent. One method of producing chitosan is by the deacetylation of chitin, which is a polysaccharide constructed from linked units of N-acetylglucosamine and having the molecular formula (C8H13NO5)n. Chitosan is hypoallergenic and has inherent anti-bacterial properties. When used as the blood clotting agent in the present invention, chitosan is formed into particles, i.e., beads, pellets, granules, rods, or any other surface morphology or combination of surface morphologies. Irrespective of the surface morphology, the particles are about 0.2 mm to about 10 mm, preferably about 0.5 mm to about 5 mm, and more preferably about 1 mm to about 2 mm in effective diameter. The particles may be produced by any suitable process.

As with the zeolites, clays, and bioactive glass, various materials may be mixed with, associated with, or incorporated into the chitosan to maintain an antiseptic environment at the wound site or to provide functions that are supplemental to the clotting functions of the chitosan. Exemplary materials that can be used include, but are not limited to, pharmaceutically-active compositions such as antibiotics, antibacterial agents, antifungal agents, antimicrobial agents, anti-inflammatory agents, analgesics, antihistamines (e.g., cimetidine, chloropheniramine maleate, diphenhydramine hydrochloride, and promethazine hydrochloride), bacteriostatics, compounds containing silver ions, wound healing agents, 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.

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, molecular sieve material, oxidized cellulose material, clay, bioactive glass, or chitosan retained therein. Although the devices of the present invention are described hereinafter as including clay as the blood clotting agent, it should be understood that the blood clotting agent may be bioactive glass, chitosan, zeolite, or oxidized cellulose, or any combination thereof. 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 clay 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 clay particles 14 therein while allowing liquid to flow through. As illustrated, the mesh 12 is shown as being flattened out, and only a few clay particles 14 are shown.

The clay particles 14 are substantially spherical or irregular in shape (e.g., balls, beads, pellets, or the like) and about 0.2 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 exotherms produced when zeolite is used as the blood clotting agent) can also be controlled.

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).

Referring now to FIG. 2, the openings defined by the mesh 12 are dimensioned to retain the clay particles 14 but to accommodate the flow of blood therethrough. Because the mesh 12 may be pulled tight around the clay particles 14, the particles may extend through the openings by a distance d. If the clay 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 clay particles 14, and the water phase thereof is wicked into the clay material, thereby facilitating the clotting of the blood. However, it is not a requirement of the present invention that the clay particles protrude through the mesh.

To apply the pouch 10 to a bleeding wound, the pouch is removed from the packaging and placed on the bleeding wound. The clay 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 clay material, thereby promoting the clotting of the blood.

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, clay (or other) 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 clay particles 14 therein while allowing the flow of blood therethrough.

The mesh 12 is stitched, glued, clamped, or otherwise mounted to the support 22. The support 22 comprises an undersurface 24 against which the clay particles 14 are held by the container 12 and a top surface 26. The undersurface 24 is impermeable to the clay 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.

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 clay 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 clay 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.

Referring now to FIG. 4, another embodiment of the present invention is a bandage, shown at 50, which comprises clay particles 14 (or some other molecular sieve material or oxidized cellulose in particle form) 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.

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.

Referring now to FIG. 5, another embodiment of the present invention comprises a device 110 having the clay particles 14 (or other blood clotting material such as zeolite, bioactive glass, chitosan, or oxidized cellulose) as described above retained within a fabric pouch. The fabric pouch is a clay-impregnated mesh 112 having hemostatic qualities, namely, the hemostatic properties of clay. The mesh 112 is not limited to being impregnated with clay, however, as other materials such as bioactive glass, chitosan, poly-N-acetylglucosamine (derived from algae), thrombin, fibrin, microporous polymer particles, microporous polysaccharide particles, gelatin sponge, microfibrillar collagen, oxidized cellulose, zeolite, or combinations of the foregoing may also be impregnated or otherwise incorporated into the mesh without deviating from the broader aspects of the present invention. The device 110 may include a support 122, thereby defining a pad. When the device 110 is a pad, the support 122 provides a surface at which pressure may be applied in the application of the device to a bleeding wound. Without the support 122, the device 110 may be used as a surgical sponge.

The clay-laden mesh 112 is defined by interconnected strands, filaments, or strips of material that are interconnected by being woven, intertwined, or integrally formed as in the above-disclosed embodiments. The mesh 112 includes particles of clay powder 15. Although the particles of clay powder 15 are shown as being concentrated along portions of the edges of the mesh 112, it should be understood that the clay powder is dispersed throughout the material from which the mesh is fabricated. Preferably, the interconnection of the strands, filaments, or strips to form the mesh 112 is such that the device 110 can flex while substantially maintaining the dimensions of the openings, thereby allowing the clay (or other) particles 14 to be retained.

Referring now to FIGS. 6 and 7, clay is impregnated into or otherwise retained by the material of the strands, filaments, or strips that define the mesh 112. In particular, the particles of clay powder 15 may be captured within a matrix material 130 such that the particles contact the bleeding tissue when the strands, filaments, or strips defining the mesh 112 are brought into contact with the wound. As is shown in FIG. 6, the clay powder 15 may be captured and held within the outer surface of the matrix material 130. In such an embodiment, the matrix material 130 is preferably sufficiently porous to facilitate the flow of blood therethrough, thus allowing liquid phases of the blood to be at least partially absorbed by the clay powder 15 prior to contacting the clay particles (or other materials) retained in the mesh 112. As is shown in FIG. 7, the clay powder may be captured so as to protrude above the surface of the matrix material 130.

Referring to FIG. 8, the clay powder 15 may be impregnated into a substrate material 132 and retained therein by any suitable method. In the impregnation of the clay powder 15 into the substrate material 132, the substrate material is generally sufficiently soft (e.g., fluid when exposed to heat) to allow for its deformation to accommodate the clay powder. The clay powder 15 may be impregnated completely into the substrate material 132, or it may be partially impregnated so as to extend out of the substrate material.

In either the embodiment of FIGS. 6 and 7 or of FIG. 8, the matrix material or the substrate material 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). The matrix material or the substrate material may also be cellulose or a cellulose derivative.

The clay-laden mesh 112 may be utilized in conjunction with a bandage, as is shown in FIG. 9. The mesh 112 (which comprises the clay powder 15) may be mounted to a flexible substrate 152 that can be applied to a wound in a manner similar to that described above with reference to FIG. 4. The mesh 112 may be stitched, glued, or otherwise mounted to the substrate 152, which may be a plastic or cloth member that is retained on the skin of an injured person or animal on or proximate the bleeding wound (e.g., via an adhesive 154).

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 may be by extrusion, milling, casting, or the like.

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.

Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US20100129427 *Nov 25, 2009May 27, 2010Biolife, L.L.C.Hemostatic Wound Dressings
Classifications
U.S. Classification424/424
International ClassificationA61F2/00
Cooperative ClassificationA61L15/18, A61L15/42
European ClassificationA61L15/18, A61L15/42
Legal Events
DateCodeEventDescription
Aug 29, 2008ASAssignment
Owner name: Z-MEDICA CORPORATION, CONNECTICUT
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:HUEY, RAYMOND J.;HORN, JEFFREY L.;LO, DENNY;REEL/FRAME:021463/0233;SIGNING DATES FROM 20080828 TO 20080829