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Wound dressing and method for controlling severe, life-threatening bleeding

a wound dressing and life-threatening technology, applied in the field of hemorrhage control wound dressings, can solve the problem of no low-cost wound dressings suitable for controlling severe life-threatening bleeding

Inactive Publication Date: 2005-06-23
HEMCON
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0018] The invention is directed to a first-aid / primary intervention wound dressing for control of severe, life-threatening bleeding. Presently there are no low cost wound dressings that are suitable for control of severe life-threatening bleeding. There is a need for this type of dressing especially in the battlefield, where typically 50% of all deaths are associated with an inability to immediately control severe bleeding. The wound dressing of the invention is capable of substantially stanching the flow of life-threatening bleeding from a wound by adhering to the wound site, sealing the wound, accelerating blood clot formation at the wound site, reinforcing clot formation at the wound site, preventing bleed out from the wound site, and substantially prohibiting the flow of blood out of the wound site.
[0034] In another embodiment, a process for preparing a compressed composite sponge for hemorrhage control comprising a) degassing chitosan biomaterial solution by heating the chitosan biomaterial solution and applying a vacuum thereto; b) freezing the chitosan biomaterial solution; c) removing water from within frozen chitosan biomaterial without damaging the structural integrity of the frozen chitosan biomaterial so that the water in the chitosan biomaterial passes from a solid phase into a gas phase; d) compressing the chitosan biomaterial at a preferred rate of about 10 mm per minute thereby obtaining a compressed sponge with a density of about 0.1 to about 0.2 g / cm3; and e) baking the compressed chitosan sponge at 80° C. for 30 minutes. Preferably, the temperature is gradually lowered over a predetermined period of time during the freezing of the chitosan biomaterial of step (b).
[0040] In another embodiment, a process for improving the mechanical traction of the compressed or compressed composite sponges comprising pressing tissue contacting sides of the sponge against a macrotextured surface is provided. Preferably, the macrotextured surface is selected from the group consisting of surfaces prepared by chemical etching, and surfaces prepared by particle blasting techniques.
[0054] In another embodiment, a process for preparing a compressed composite sponge for hemorrhage control comprising a) degassing biomaterial solution by heating the biomaterial solution and applying a vacuum thereto; b) freezing the biomaterial solution; c) removing water from within frozen biomaterial without damaging the structural integrity of the frozen biomaterial so that the water in the biomaterial passes from a solid phase into a gas phase; d) compressing the biomaterial at a preferred rate of about 10 mm per minute thereby obtaining a compressed sponge with a density of about 0.1 to about 0.2 g / cm3; and e) baking a compressed sponge at 80° C. for 30 minutes is provided. Preferably, the temperature is gradually lowered over a predetermined period of time during the freezing of the biomaterial of step (b). Preferably, the temperature of step (b) is a final freezing temperature of not more than about −5° C. More preferably, the temperature of step (b) is a final freezing temperature of not more than about −35° C. Most preferably, the temperature of step (b) is a final freezing temperature of not more than about −25° C. Preferably, the water removal is performed by freeze-drying the frozen biomaterial. The process may further comprise a step of adding argon, nitrogen and helium back into the degassed chitosan solution before the freezing. The sponge may be compressed sponge is sterilized. Preferably, the compressed sponge is sterilized by gamma irradiation.
[0059] In another embodiment, a process for improving the mechanical traction of the compressed or compressed composite sponges comprising pressing tissue contacting sides of the sponge against a macrotextured surface is provided. Preferably, the macrotextured surface is selected from the group consisting of surfaces prepared by chemical etching, and surfaces prepared by particle blasting techniques.

Problems solved by technology

Presently there are no low cost wound dressings that are suitable for control of severe life-threatening bleeding.

Method used

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  • Wound dressing and method for controlling severe, life-threatening bleeding
  • Wound dressing and method for controlling severe, life-threatening bleeding
  • Wound dressing and method for controlling severe, life-threatening bleeding

Examples

Experimental program
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example 1

Hemorrhage Control Testing

[0146] Table 1 provides a list of the main chitosan materials acquired for hemorrhage control testing. With the exception of the Gelfoam™+thrombin, and Surgicel™ controls for swine spleen experiments and the Johnson and Johnson 4″×4″ gauze control for use in swine aortic perforations, the dressing materials described here were all chitosan-based.

TABLE 1CarbomerGenisSourceProtosan (Norway)(USA)Primex (Norway)(Iceland)Sample NameG213G113CL213CL1139012-75-4ChitoclearBatch Number511-583-005-370-01607-783-02310-490-01VA-UY992BN 381TM 752TM 751SO11115-101Bio- SourceCrab & / orCrab & / orCrab & / orCrab & / orShrimpShrimpShrimpShrimpShrimpShrimpShrimpShrimpShrimpAppearanceFine whiteFine whiteFine whiteFine whiteYellowedFine off-Fine off-Fine off-Off-whitepowderpowderpowderpowderpowder +whitewhitewhiteflakespeckspowderpowderpowderViscosity cps1081213312NANA1091561216(1% soln)% Dry Matter 93.090.3 90.893.9NANA 97.7 97.6 93% Protein 0.2 0.2 0.1 0.1NANA   % Deacetylation 8...

example 2

Preparation and Evaluation of Wound Dressing

[0150] Hemostatic wound dressings were prepared as follows: [0151] a) Dry chitosan powder or flake with degree of deactylation above 85%, less than 26 ppm metallic component and greater than 90% dry solids content was made in a 2% aqueous solution (w / w) with about 2 or 1% acetic acid (w / w) at 40° C. [0152] b) The solution of chitosan from a) above was degassed under reduced pressure at up to about 500 mTorr under agitation for at least 5 minutes and poured into a mold to a depth of 1.7 cm. Certain low-density, foam structures exhibited problems due to their ready dissolution in a bleeding field. These problems were generally avoided by thorough degassing of the solution. [0153] c) The mould containing the degassed chitosan solution was frozen by cooling from room temperature to −45° C. A linear cooling ramp was used over a 90 minute period, and the temperature was maintained at −45° C. for at least another hour. [0154] d) The frozen chito...

example 3

Hepatic Hemorrhage Control in Swine Liver Model

[0196] The US Army Science and Technology Objective (STO) A, Hemorrhage Control, was established in 2000 to advance the need for hemorrhage control on the battlefield. The general strategic objective of the STO can be summarized as the development of products and methods that will reduce the number of deaths due to hemorrhage in battlefield casualties. The requirements for hemorrhage control products and methods were stated thus:

[0197] They must be practicable for use by one or more of the following: self (wounded combatant), buddy (fellow non-medical soldier who aids the wounded soldier), combat lifesaver, combat medic, physician assistant, and battalion surgeon. They must be practicable for use in far forward field conditions including rugged terrain, limited visibility, and environmental extremes. Products and methods must not require external electrical sources. All devices must be man-portable and durable. It is expected that pro...

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Abstract

This invention is directed to advanced hemorrhage control wound dressings, and methods of using and producing same. The subject wound dressing is constructed from a non-mammalian material for control of severe bleeding. The wound dressing for controlling severe bleeding is formed of a biomaterial comprising chitosan, a hydrophilic polymer, a polyacrylic polymer or a combination thereof. The kind of severe, life-threatening bleeding contemplated by this invention is typically of the type not capable of being stanched when a conventional gauze wound dressing is applied with conventional pressure to the subject wound. The wound dressing being capable of substantially stanching the flow of the severe life-threatening bleeding from the wound by adhering to the wound site, to seal the wound, to accelerate blood clot formation at the wound site, to reinforce clot formation at the wound site and prevent bleed out from the wound site, and to substantially prohibit the flow of blood out of the wound site.

Description

FIELD OF THE INVENTION [0001] This invention is directed to hemorrhage control wound dressings, and methods of using and producing such dressings. The subject wound dressing is constructed from a non-mammalian material for the control of severe bleeding. The wound dressing is formed of a biomaterial comprising chitosan and / or other hydrophilic polymers for controlling severe bleeding. The material may alternatively comprise polyacrylic acid or a combination of polyacrylic acid with other polymers. The kind of severe, life-threatening bleeding contemplated by this invention is of the type not capable of being stanched when a conventional gauze wound dressing is applied with conventional pressure to the wound. The wound dressing is capable of substantially stanching the flow of life-threatening bleeding from a wound by adhering to the wound site, sealing the wound, accelerating blood clot formation at the wound site, reinforcing clot formation at the wound site, preventing bleed out f...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): A61F13/00A61F13/02A61F15/00A61F17/00A61L15/42
CPCA61F13/02A61F13/0276A61L15/425A61F2013/00472A61F17/00A61F13/0223A61F13/0226A61P17/02A61L15/00A61L15/10A61L15/12A61L15/14
Inventor CAMPBELL, TODD D.WIESMANN, WILLIAM P.MCCARTHY, SIMON J.
Owner HEMCON
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