Abstract:
In one aspect, an apparatus for promoting hemostasis includes oxidized cellulose in the form of a compressible, shapeable mass that is formed into a sheet for placement on a bleed site. In a second aspect, a sleeve for promoting hemostasis includes a tubular shell having at least one open end and oxidized cellulose material attached to an inner surface of the tubular shell. The open end of the tubular shell is dimensioned to receive a limb such that donning the sleeve causes at least a portion of the oxidized cellulose material to be placed in contact with a bleeding wound. In a third aspect, a bandage includes a substrate and oxidized cellulose material attached to a surface of the substrate. The oxidized cellulose material is arranged to contact a bleeding wound when the bandage is applied thereto.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]     This application claims the benefit of U.S. Provisional Patent Application No. 60/810,447, filed on Jun. 1, 2006, the contents of which are incorporated herein by reference in their entirety. 
     
    
     TECHNICAL FIELD  
       [0002]     The present invention relates generally to hemostatic devices and, more particularly, to devices that allow hemostatic materials incorporated therein to be brought into contact with wound sites.  
       BACKGROUND OF THE INVENTION  
       [0003]     Blood is a liquid tissue that includes red cells, white cells, corpuscles, and platelets dispersed in a liquid phase. The liquid phase is referred to as plasma and 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.  
         [0004]     In a wide variety of circumstances humans (as well as animals) can be wounded, thereby resulting in bleeding. 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 stop the flow of blood in a timely manner.  
         [0005]     In an effort to address the above-described problems, materials and devices have been developed for controlling excessive bleeding in situations where conventional aid is unavailable or less than optimally effective. Although these materials and devices 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 and can be difficult to apply as well as remove from a wound.  
         [0006]     In situations in which traumatic wounds are experienced (such as automobile or motorcycle accidents) and where multiple wounds are inflicted on a victim over multiple portions of the victim&#39;s body, some wounds may be inflicted on both the anterior and posterior surfaces of the victim. First aid may be administered to treat the wounds on one surface, but other wounds on another surface may be more difficult to attend to. For example, a victim&#39;s wounds on the front and sides of his legs may be treated while the victim is laying on his back, but the wounds on the back of his legs may be inaccessible because of the need to maintain the victim face up, particularly during transport of the victim to a medical facility. Furthermore, wounds on the posterior surfaces of a victim&#39;s arms, legs, and head may be completely overlooked during transport of the victim and may only become apparent upon closer inspection when the victim is moved from a gurney or stretcher to an operating table. This problem is further exacerbated in cases where a victim is covered in blood and other debris as is sometimes the case in automobile accidents.  
         [0007]     Based on the foregoing, it is the 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  
       [0008]     Disclosed herein are devices directed to the clotting of blood and the dressing of wounds. The devices generally comprise bandages that can be worn directly on wounds and that contain oxidized cellulose materials that can minimize or stop the flow of blood by absorbing at least portions of the liquid phases of the blood, thereby promoting clotting. When applied to a wound, the oxidized cellulose materials accelerate hemostasis by facilitating the formation of a coagulum plug over the wound. Although the devices are particularly suited for use in treating wounds resulting from traumatic injury, the present invention is not limited in this regard and the devices can be used in various surgical procedures in which it is desired to arrest the flow of blood.  
         [0009]     According to one aspect, the present invention resides in an apparatus for promoting hemostasis that includes oxidized cellulose in the form of a compressible, shapeable mass that is formed into a sheet for placement on a bleed site. The oxidized cellulose is in strand form and may be woven or unwoven. When the apparatus is placed onto the bleed site and is contacted with blood flowing therefrom, a clotting effect is realized.  
         [0010]     In a second aspect, the present invention resides in a sleeve for promoting hemostasis. The sleeve includes a tubular shell having at least one open end and oxidized cellulose material attached to an inner surface of the tubular shell. The open end of the tubular shell is dimensioned to receive a limb such that when treating a bleeding wound, donning the sleeve causes at least a portion of the oxidized cellulose material to be placed in contact with the bleeding wound. Upon contacting the bleeding wound with the oxidized cellulose material, a clotting effect is realized.  
         [0011]     In a third aspect, the present invention resides in a bandage applicable to a bleeding wound. The bandage includes a substrate and oxidized cellulose material attached to a surface of the substrate. The oxidized cellulose material is arranged to contact the bleeding wound when the bandage is applied thereto. An adhesive may be applied to the substrate as needed to adhere the bandage to skin adjacent the wound, thereby facilitating the retention of the oxidized cellulose material in contact with tissue of the bleeding wound.  
         [0012]     In any embodiment of the present invention, pharmaceutically-active compositions may be incorporated into the oxidized cellulose. Such pharmaceutically-active compositions include, but are not limited to, antibiotics, antifungal agents, antimicrobial agents, anti-inflammatory agents, anti-viral agents, analgesics, bone morphogenic proteins, bone-stimulating agents, compounds containing silver ions, corticosteroids, osteoblast stimulators, odontoblast stimulators, ascorbic acid, tranexamic acid, rutin, thrombin, botanical agents, and combinations of the foregoing.  
         [0013]     One advantage of the present invention is that the devices can be readily removed from their packaging and either self-administered or administered by care-giving personnel in a single step. More specifically, because the devices incorporate hemostatic or blood clotting materials incorporated therein in pre-measured amounts, the need for applications of ointments, salves, creams, or other compositions followed by dressings of bandages and the application of pressure (to initiate clotting) is eliminated. In effect, the treatment process is streamlined, which may be of particular advantage in instances in which treatment is administered as first aid for traumatic injury (e.g., in the back of an ambulance or on a battlefield) in transit to a hospital or in anticipation of more sophisticated medical care.  
         [0014]     The oxidized cellulose of the devices of the present invention is also advantageously biocompatible with living tissue. This biocompatibility allows the oxidized cellulose, which is a form of cotton, to be resorbed into the wound during the healing process. Resorption of the oxidized cellulose material into the wound, particularly when the material is in unwoven form, produces no detrimental effects on the living tissue.  
         [0015]     Still another advantage of the present invention is that the proper dose of oxidized cellulose material can be readily applied to an open wound. Especially when the device is a sleeve or the like containing oxidized cellulose material, the device can be readily removed from sterilized packaging and used to treat the wounds directly at the points from which blood emanates to initiate clotting of the blood without inadvertently applying material outside the wound area. Guesswork, estimation, or calculation of the amounts of oxidized cellulose material for application to a bleeding wound is eliminated. Accordingly, little or no material is wasted. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]      FIG. 1  is a magnified photographic image taken by a scanning electron micrograph of oxidized cellulose.  
         [0017]      FIG. 2  is a perspective view of oxidized cellulose in sheet form of the present invention.  
         [0018]      FIG. 3  is a perspective view of oxidized cellulose attached to a substrate to form a pad of the present invention.  
         [0019]      FIG. 4  is a perspective view of an adhesive bandage, of the present invention, incorporating oxidized cellulose.  
         [0020]      FIG. 5  is a perspective view of a pad, of the present invention, securable using hook-and-loop material and incorporating oxidized cellulose.  
         [0021]      FIG. 6  is a perspective view of a pad, of the present invention, securable using straps and incorporating oxidized cellulose.  
         [0022]      FIG. 7  is a perspective view of a pad, of the present invention, securable using straps and incorporating oxidized cellulose.  
         [0023]      FIG. 8  is a perspective view of a sleeve, of the present invention, having oxidized cellulose attached to an inner surface thereof.  
         [0024]      FIG. 9  is a perspective view of a sleeve, of the present invention, having straps for securing the sleeve to a limb of a wearer. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0025]     Oxidized cellulose 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.  
         [0026]     Oxidized cellulose may be manufactured by the action of nitrogen dioxide gas (NO 2 ) 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.  
         [0027]     One method of generating nitrogen dioxide gas is by the catalytic reaction of manganese dioxide or manganese disulfide on concentrated nitric acid. Any amount of nitrogen dioxide can be generated by the metered addition of nitric acid to the manganese dioxide or manganese disulfide catalyst. In such a reaction, dinitrogen tetroxide (N 2 O 4 ), which is a dimer of nitrogen oxide, is also formed in addition to the nitrogen dioxide. The formation of the dimer does not have an interfering effect on the oxidation of the cellulose.  
         [0028]     In this method of nitrogen dioxide generation, unaltered cellulose fibers are introduced into a reaction vessel, and concentrated nitric acid is metered into a second enclosed vessel containing manganese dioxide powder. Nitrogen dioxide gas is evolved, which is piped to the reaction vessel containing the cellulose fibers. Once the nitrogen dioxide gas is piped to the reaction vessel containing the cellulose fibers, the reaction vessel is purged with an excess amount of nitrogen dioxide and left sealed for 36 hours. This may alternatively be done in a pressurized environment of nitrogen dioxide. The oxidized cellulose is then removed and washed in dilute sodium bicarbonate solution, followed by multiple agitated rinses with distilled water. Alternatively, the oxidized cellulose may be degassed using other suitable means. The resulting oxidized cellulose is thus sufficiently carboxylated to provide a desirable hemostatic effect on a bleeding wound. The resulting fibers can also be autoclaved before use.  
         [0029]     Another method of generating nitrogen dioxide gas is by the reaction of formaldehyde with concentrated nitric acid. This reaction, however, is not catalytic. In particular, formaldehyde is consumed in the reaction and is thus depleted. The formaldehyde readily reacts with the nitric acid to generate the nitrogen dioxide and the dimer. Again, the nitrogen dioxide gas is piped to the reaction vessel containing the cellulose fibers, and the reaction vessel is purged with excess nitrogen dioxide and sealed. The oxidized cellulose is removed, washed, and rinsed.  
         [0030]     Referring to  FIG. 1 , the oxidized cellulose generated by either method is a mass of unwoven cellulose strands. The strands are loosely intermingled and easily compressed. The interstices between adjacent strands define areas in which the blood collects and the solids thereof agglomerate to facilitate the formation of clots.  
         [0031]     The compressibility of the unwoven cellulose strand mass allows the material to be formed into sheets that can be cut to any desired size and used as bandages. Referring now to  FIG. 2 , a sheet of compressed, unwoven, oxidized cellulose is shown generally at  10  and is hereinafter referred to as “sheet  10 .” Sheet  10  is defined by a thickness t, which can vary depending upon the intended application. In particular, the thickness t can be thicker for applications in which heavy bleeding is encountered or thinner for applications in which an exudate from a wound is slight, such as from a burn or a mild abrasion of flesh. An increased thickness t provides enhanced compressibility to the sheet  10 , which allows for increased absorbability of blood and other bodily fluids. Although shown as being rectangular, the sheet  10  can comprise any shape suitable or desired for application to a wound.  
         [0032]     Referring now to  FIG. 3 , the sheet  10  may be attached to a substrate  12  to define a pad  20 . Although the sheet  10  itself possesses some inherent absorptive qualities, an additional layer  18  of absorbent material may be disposed intermediate the substrate  12  and the sheet to absorb and accumulate excess blood and other bodily fluids that seep through the sheet when placed on a wound, thereby preventing or limiting wetting the substrate. The pad  20  may be approximately square as shown, or it may be elongated in a lengthwise dimension to approximate a rectangle. Optionally, the pad  20  may be an elongated strip and rolled during storage, thus being able to be unrolled and wound around a body part to contact a wound. By configuring the pad  20  as a rollable strip, the pad can be wound around the limbs, torso, or head of a wounded patient as necessary (e.g., intertwined among digits and the like).  
         [0033]     The substrate  12  may be any suitable material conducive to being placed in proximity with a wound. Preferably, the substrate  12  is elastically deformable. This quality, in combination with the compressibility and elastic deformability of the oxidized cellulose sheet  10 , allows the pad  20  to be wrapped tightly over portions of the wounded person&#39;s body so as to maintain pressure on the wound. Suitable materials for the substrate  12  include, but are not limited to, cloth (e.g., cotton, linen, wool, and the like) particularly in gauze form, metal, paper, polymeric material, synthetic or natural rubber, breathable synthetic materials (e.g., fluoropolymer-based material bonded to nylon or polyester fabric), combinations of the foregoing, and the like.  
         [0034]     Referring now to  FIG. 4 , the substrate  12  may include an adhesive  22  disposed thereon to facilitate the attachment of the substrate to the skin adjacent the wound, thereby defining an adhesive bandage  26 . The substrate  12  may include holes  28  formed or otherwise disposed therein to allow moisture (perspiration) to evaporate from the skin and to allow air to circulate to the wound when the bandage  26  is worn. The layer  18  of absorbent material may or may not be disposed intermediate the substrate  12  and the sheet  10 . Once adhered to the skin of the user, the oxidized cellulose of the sheet  10  is held into direct contact with the wound, thereby initiating the clotting of blood.  
         [0035]     Referring now to  FIGS. 5-7 , fasteners may be used to allow the substrate to be held on the skin adjacent the wound. In  FIG. 5 , one exemplary embodiment of a pad is depicted generally at  120 . The pad  120  includes the sheet  10  of compressed, unwoven, oxidized cellulose attached to an elastically deformable substrate  112  having holes  128 . Fasteners, such as hook-and-loop material, are used to secure the pad  120  to itself adjacent the wound. As is shown, the hook-and-loop material includes a hook material portion  125  attached proximate an edge of the substrate  112  and a loop material portion  127  attached proximate a second edge of the substrate. Although the substrate  112  is referred to as being elastically deformable, the present invention is not limited in this regard, and the substrate may be non-elastic.  
         [0036]     Referring to  FIG. 6 , another exemplary embodiment of a pad is depicted generally at  220 . The pad  220  includes the sheet  10  of oxidized cellulose attached to an elastically deformable substrate  212  having holes  228 . Fastening straps, depicted generally by reference numeral  231 , are used to secure the pad  220  to itself adjacent the wound. The fastening straps  231 , two of which are shown, each comprise a first member  233  and a second member  235 , the first member being connectable to the second member via any suitable device such as hook-and-loop material or the like. The first members  233  are generally attached to the substrate  212  proximate an edge that is opposite the edge at which the second members  235  are attached. Preferably, at least the first member  233  is adjustable in length using a buckle  237 . Although the substrate  212  is referred to as being elastically deformable, the present invention is not limited in this regard, and the substrate may be non-elastic.  
         [0037]     In  FIG. 7 , another exemplary embodiment of a pad is depicted generally at  320 . The pad  320  includes the sheet  10  of oxidized cellulose attached to an elastically deformable substrate  312  having holes  328 . Fastening straps  331  are used to secure the pad  320  to itself adjacent the wound. The fastening straps  333 , two of which are shown, each comprise a first member  333  that is attachable to a second member  335  mounted to the substrate  312 . Devices that may be used to facilitate the connection of the fastening straps  333  to the second members  335  include, but are not limited to, hooks  341  (on the fastening straps) and eyelets  343  (on the second members). Preferably, the fastening straps  333  are adjustable in length using a buckle  337 . Although the substrate  312  is referred to as being elastically deformable, the present invention is not limited in this regard, and the substrate may be non-elastic.  
         [0038]     Referring now to  FIG. 8 , the sheet  10  is positioned adjacent a tubular shell  30  to define a sleeve  36 . The tubular shell  30  can be a nylon outer surface with an inner lining stitched thereto and filled with a compressible filler material. The sheet  10  is stitched, glued, or otherwise mounted to an inner surface of the tubular shell  30  (with or without the layer of absorbent material positioned therebetween). The tubular shell  30  is dimensioned such that it can be pulled over a limb, the torso, or even the head of a wounded person to bring the oxidized cellulose material of the sheet into contact with a wound.  
         [0039]     In some embodiments, the sleeve  36  may be securable to the arm, leg, or torso of a victim via one or more straps  40 , as shown in  FIG. 9 . Portions of the straps  40  may be affixed to the outer surface of the tubular shell  30  at various points along the length of the sleeve  36  such that belt portions of the straps  40  may be wrapped around the sleeve and secured upon themselves. The straps  40  may be secured using hook-and-loop material  42 , with one of the hook portion and the loop portion being disposed along the lengths of the belt portions and the other of the hook portion and the loop portion being disposed on the outer surface of the tubular shell  30 . Alternately, the straps  40  may be nylon webbing or similar material, adjustable lengthwise using buckles, and securable to themselves using buttons, hooks, or quick-disconnect fasteners.  
         [0040]     To utilize the sleeve  36  to dress a bleeding wound, the sleeve is removed from the packaging (if any) and held such that one end of the tubular shell  30  is opened. The sleeve  36  is then pulled over the wounded person&#39;s leg or arm such that the wound is covered. If the sleeve  36  has straps  40  attached to the outer surfaces of the tubular shell  30 , the straps may be wrapped around the tubular shell and secured upon themselves. Once positioned on the victim, the oxidized cellulose in the sheet  10  contacts 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 oxidized cellulose, thereby promoting clotting of the blood.  
         [0041]     Other forms of the oxidized cellulose, such as those in woven form, are within the scope of the invention and suitable for use as sheet  10  in any of the above-described embodiments. After manufacture of any of the devices described above, the devices are preferably packed into containers that ensure the sterility of the devices until the containers are opened.  
         [0042]     Various materials may be mixed with, associated with, disseminated throughout, embedded into, or incorporated into the oxidized cellulose to maintain an antiseptic environment or to provide functions that are supplemental to the hemostatic functions of the oxidized cellulose. Such materials can be used to stimulate cells, to promote adhesion to soft tissue (e.g., mucosa), or to promote adhesion to hard tissue (e.g., bone) to prevent dislodgement of the coagulum plug during the healing process.  
         [0043]     One particular use may be for the acceleration of the healing process by effecting a timed release of medication into the tissue adjacent the wound. Accordingly, the material is dispensed into the wound simultaneously with the clotting function. 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, anti-viral agents, analgesics (e.g., cimetidine, chloropheniramine maleate, diphenhydramine hydrochloride, and promethazine hydrochloride), bone morphogenic proteins, bone-stimulating agents, compounds containing silver ions, corticosteroids, osteoblast stimulators, odontoblast stimulators, 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.  
         [0044]     After the cellulose is oxidized and either before or after it has been shaped into a device having a particular form (sheet  10  or the like), the drugs or other ancillary materials may be mixed with, associated with, disseminated throughout, embedded into, or incorporated into the cellulose using any suitable technique. Some methods may be as simple as shaking a dry powder into the fibrous matrix of the cellulose. Other methods may involve soaking the cellulose in aqueous solutions of the particular medication. Still other methods involve pressing the materials in slurry or particle form into the device. Liquid medications can also be absorbed into the fibers immediately prior to application of the device for subsequent delivery to a wound. Multiple ways exist for incorporation of these materials into the oxidized cellulose devices of the present invention, as will become evident during practice.  
         [0045]     When placed on or in a wound, hemostasis can be established while the one or more pharmaceutically-active compositions are released into the wound. Upon removal of the device, any oxidized cellulose adhered to the coagulum plug can remain in place and be physiologically resorbed by the body.  
         [0046]     Additionally, if the oxidized cellulose is configured to have a particular orientation in the wound (e.g., if the material is rolled or cut to fit into a laceration or puncture), the pharmaceutically-active composition may be located so as to effect a “site specific” delivery. For example, when a sheet of oxidized cellulose material is used to pack an open wound created by the removal or disruption of some amount of flesh, the pharmaceutically-active composition may be concentrated in the material around a peripheral edge thereof or in an outer layer, thus administering an application of the composition directly to the tissue of the wound without providing excess composition (e.g., in the center of the sheet) that is unlikely to have an effect on the healing process.  
         [0047]     There are multiple clinical applications for the oxidized cellulose. It is especially indicated for first aid applications, namely for arresting the flow of blood from minor lacerations and abrasions and accelerating hemostasis. It is also suitable for providing an immediate cessation of blood flow resulting from traumatic injury, such as more severe lacerations and abrasions as well as puncture wounds. In both medical and dental surgical applications, it can be utilized in to fill voids that result from cyst removal, to deliver drugs after bone surgery, to deliver drugs that promote the healing of pulp after pulp exposures and other clinical cases in which hemostasis is desired with the added benefit of delivering drugs for the purpose of controlling infections and the acceleration of healing. It is also especially indicated for patients who have a tendency to profusely bleed such as hemophiliac patients or patients taking blood thinning medications. In veterinary practice, the devices can be especially useful in less-than-septic conditions, e.g., in barnyards, kennels, and the like. A myriad of other uses of this device will become apparent during routine use by medical, dental, and veterinary practitioners.  
         [0048]     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.