Haemostatic material

Abstract

The present invention relates to a haemostatic material comprising a carrier layer and a material for wound contact comprising at least one haemostat in particulate, granular, powder, flake or short fibrous form. Such a haemostatic material is useful, for example, in reducing or stopping bleeding of a physiological target site in a person or animal, and can also be used to stem bleeding during medical procedures.

Claims

1. A haemostatic material comprising: a carrier layer comprising a non-woven material, woven gauze, a film, a foam or a sheet gel, and a wound contact layer being a single layer comprising a mixture of at least one haemostat and an adhesive, the wound contact layer being bonded directly to the carrier layer, wherein the at least one haemostat is in a form selected from the group consisting of: particulate, granular, powder, flake, and short fibrous, wherein said haemostat comprises a chitosan salt, and wherein the haemostat or adhesive is sufficiently water sensitive to weaken the bond between the haemostat and the adhesive upon contact with a fluid, such that when the wound contact layer is wet with blood a portion of the haemostat will remain at the wound site if the carrier layer is removed.

2. A haemostatic material according to claim 1 wherein both surfaces of the carrier layer are at least partially coated with haemostat.

3. A haemostatic material according to claim 1 further comprising a material which is degradable in the body.

4. A haemostatic material according to claim 1 wherein the haemostat comprises two or more haemostats.

5. A haemostatic material according to claim 1, comprising wound contact layer on an upper and lower surface of the carrier layer.

6. A haemostatic material according to claim 1, further comprising a soluble, dispersible or removable retaining layer on top of the wound contact layer.

7. A haemostatic material according to claim 6, wherein the soluble, dispersible or removable retaining layer is formed from a material susceptible to metabolisation within a human or animal body.

8. A haemostatic material according to claim 1, wherein the chitosan salt comprises one or more salts selected from the group consisting of chitosan acetate, chitosan lactate, chitosan succinate, chitosan malate, and chitosan acrylate.

9. A haemostatic material according to claim 8, wherein the chitosan salt comprises chitosan succinate.

10. A haemostatic material according 1 wherein the chitosan salt constitutes at least about 5% by weight of the haemostat.

11. A haemostatic material according to claim 1, wherein the haemostat is granular.

12. A haemostatic material according to claim 1 further comprising a medical surfactant.

13. A haemostatic material according to claim 12, wherein the medical surfactant constitutes from about 0.001 to about 10% by weight of the haemostat.

14. A haemostatic material according to claim 12 wherein the medical surfactant comprises one or more components selected from the group consisting of block copolymers based on ethylene oxide and propylene oxide, fatty acids, fatty acid salts, silicone based surfactants and emulsifiers.

15. A haemostatic material according to claim 14, wherein the medical surfactant is a fatty acid selected from lauric acid and oleic acid.

16. A haemostatic material according to claim 1 further comprising at least one inert material.

17. A haemostatic material according to claim 16, wherein the at least one inert material comprises one or more selected from the group consisting of cellulose, fumed silica, sand, clay, alginate, microcrystalline cellulose, oxidised regenerated cellulose, polyethylglycol, guar gum, xanthan gum, chitosan, chitosan derivatives, chitin, sucrose, lactose, pectin, carboxymethylcellulose, ground corn meal, collagen, gelataine, polyvinylalcohol, acrylic acid, acrylate (co)polymers, crosslinked acrylic acid-based polymers, barium sulphate, clay, lactose, sucrose, starch, and combinations of any two or more thereof.

18. A haemostatic material according to claim 16 wherein the inert material constitutes up to about 95% by weight of the haemostat.

19. A haemostatic material according to claim 1 wherein the haemostat comprises particles which cannot pass through a 200 mesh sieve.

20. A haemostatic material according to claim 1 wherein the adhesive layer comprises a bonding agent wherein the bonding agent is a meltable material.

21. A haemostatic material according to claim 1 wherein the carrier layer is degradable in a human or animal body.

22. A haemostatic material according to claim 1 wherein the carrier layer comprises a viscose non-woven material.

23. A haemostatic material according to claim 1 wherein the carrier layer comprises a material selected from the group consisting of woven gauze, a film, foam, and a sheet gel.

24. A haemostatic material according to claim 12 wherein the particle size of the haemostat and the particle size of the medical surfactant are equivalent.

25. A haemostatic material according to claim 1 wherein the haemostat has a pH of from about 3.5 to about 8.0.

26. A haemostatic material according to claim 1 further comprising an absorbent layer.

27. A haemostatic material according to claim 1 wherein the material comprises part of a first aid plaster.

28. A haemostatic material according to claim 1 wherein the material further comprises a quantity of a substance which is opaque to X-rays.

29. A haemostatic wound dressing comprising: a dressing and a haemostatic material comprising a carrier layer comprising a non-woven material, woven gauze, a film, a foam or a sheet gel, and a wound contact layer being a single layer comprising a mixture of at least one haemostat and an adhesive, the wound contact layer being bonded directly to the carrier layer, wherein the at least one haemostat is in a form selected from the group consisting of: particulate, granular, powder, flake, and short fibrous, wherein said haemostat comprises a chitosan salt, and wherein the haemostat or adhesive is sufficiently water sensitive to weaken the bond between the haemostat and the adhesive upon contact with a fluid, such that when the wound contact layer is wet with blood a portion of the haemostat will remain at the wound site if the carrier layer is removed.

30. A haemostatic material according to claim 1, wherein the chitosan salt is of an organic acid.

31. A haemostatic material for application to a wound site, comprising: a carrier layer comprising a non-woven material having an upper surface and a lower surface; and a haemostatic wound contact layer adhered to the upper surface of said carrier layer, said haemostatic wound contact layer comprising a mixture of chitosan salt haemostat and a bonding agent, said mixture being applied directly to said upper surface of said carrier layer by heat, said wound contact layer being a single layer, said chitosan salt haemostat being provided in a physical form selected from the group consisting of powder, particulate, granular, flake and fiber, said bonding agent being provided in a granular form, said bonding agent being at least partially water soluble, wherein said haemostat and said bonding agent are mixed together prior to application to said carrier material, scatter coated onto said carrier material, and adhered to said carrier material by heat thus forming a water soluble wound contact layer on said upper surface of said carrier material, said wound contact layer being sufficiently water sensitive to weaken the adhesive bonds when the wound contact layer is wet thus releasing the haemostat from the wound contact layer for therapeutic effect and whereby at least a portion of the haemostat remains in the wound when the carrier layer is removed.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention will now be described further by way of example with reference to the following examples and figures which are intended to be illustrative only and in no way limiting upon the scope of the invention.

(2) FIG. 1 shows a representation of a haemostatic material according to the invention having an adhesive layer and a haemostat as separate layers.

(3) FIG. 2 shows a representation of a haemostatic material according to the invention with the adhesive layer and haemostat mixed together to form one layer.

(4) FIG. 3 shows a representation of a haemostatic material according to the invention with the adhesive layer and haemostat mixed together to form one layer and a soluble, dispersible or removable retaining layer thereon.

(5) FIG. 4 shows a representation of a haemostatic material according to the invention with a mixed adhesive/haemostat layer situated on either side of the carrier layer.

(6) FIG. 5 shows a haemostatic material according to the invention.

(7) FIG. 6 shows a close-up view of a haemostatic material according to the invention.

(8) FIG. 7 shows a wound being created in a pig by a vascular puncture to the artery made using a 16 gauge needle.

(9) FIG. 8 shows a 1 cm1 cm sheet of the haemostatic material according to the invention being applied to the wound to stem the blood flow after a specified bleed time.

(10) FIG. 9 shows a haemostatic material according to the invention being used in stemming blood flow in a pig. Steady compression is being applied for up to 5 minutes as required.

(11) FIG. 10 shows a 4 cm4 cm sheet of the haemostatic material according to the invention in use in stemming blood flow in a pig.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(12) FIG. 1 shows the haemostat 2 located on top of the adhesive layer 4 which is in turn located on the carrier layer 6. In this embodiment, the adhesive layer and the haemostat constitute separate and distinct layers.

(13) According to another embodiment of the invention the haemostat 2 may be mixed with the adhesive layer 4 to form a combined layer 8. This is shown in FIG. 2. The combined layer 8 is located on top of the carrier layer 6.

(14) In addition to the embodiment depicted in FIG. 2, a soluble, dispersible or removable retaining layer 10 may be added on top of the combined layer 8. This is shown in FIG. 3. When in use in reducing or stopping blood flow from a wound, the soluble, dispersible or removable retaining layer 10 is dissolved by or dispersed in bodily fluids, exposing the combined layer 8 below it.

(15) In FIG. 4 it can be seen that two combined layers 8 may be employed in the haemostatic material of the invention, one above the carrier layer 6 and one below. This allows for more effective reduction and stopping of blood flow in wounds which it is possible to close around the material of the invention.

(16) FIG. 5 simply shows a view of the haemostatic material 12 of the invention which is about to be put into use in reducing or stopping blood flow from a wound.

(17) FIG. 6 shows a close-up view of a sample of the haemostatic material 12 of the invention. The non-uniform texture of the carrier layer 6 can be clearly seen.

(18) FIG. 7 shows a wound being created in a pig by a vascular puncture to the artery made using a 16 gauge needle. The wound is allowed to bleed for a period of time, usually about 60 seconds, before the haemostatic material 12 is applied to the wound. Then a quantity of the haemostatic material 12, in this instance a 1 cm1 cm sheet, is applied to the wound (FIG. 8) to stem the blood flow. Steady compression is applied to the wound to ensure maximum contact between the material and the wound (FIG. 9). The compression may be maintained for up to 5 minutes as required.

(19) After the period of compression and when bleeding has been stopped, the haemostatic material 12 is left in place to prevent bleeding restarting. A 4 cm4 cm sheet of the haemostatic material 12 is shown in this role in FIG. 10. It can be seen where the haemostatic material 12 has absorbed the blood.

Example 1

(20) A granular haemostat (Celox) was bonded to a 120 gsm non-woven material (75% Viscose (Danufil-2) Fibres/25% polyolefin Fibres) made using a low melt copolyester resin with a melting range of 58-61 C. 40 gsm of resin was used, together with 60 gsm of Celox.

(21) The Celox powder and bonding agent granules were blended together, and the combination powder then scatter coated onto the non-woven material in a continuous moving web. The web was carried on a heated moving belt which passed under, a second heated moving belt, the two belts applying heat and compression to the coated web to fuse the bonding agent and the Celox powder to the web.

(22) The heat bonding process can be altered to change the degree of bonding. Heat, pressure and time (i.e. the speed of the moving belt) can all be varied as desired.

(23) The resulting surface of the haemostatic material was rough and fluffy (see FIGS. 5 and 6).

(24) The coated heat bonded web was then wound to form a roll. The resulting material was cut into 5 cm5 cm squares, packaged and sterilised.

(25) A hole was made in the femoral artery of a 100 lbs swine using a 16 gauge needle. The wound bled severely. The material was applied to the wound site with finger pressure for 3 minutes. The bleeding was robustly stopped. After 3 minutes the material was removed from the bleeding area. The bleeding did not restart.

(26) Another hole was made in the femoral artery of a 100 lbs swine using a 16 gauge needle. The wound bled severely. The material was held over the wound site with minimal pressure for 30 seconds. Even with this minimal treatment the bleeding was robustly stopped. After 3 minutes the material was removed from the bleeding area. Again, the bleeding did not restart.

Example 2

(27) A granular haemostat (Celox) was bonded to a 120 gsm non-woven material (75% Viscose (Danufil-2) Fibres/25% polyolefin Fibres) made using a low melt copolyester resin with a melting range of 58-61 C. 40 gsm of resin was used, together with 40 gsm of Celox.

(28) The Celox powder and bonding agent granules were blended together and the combination powder then scatter coated onto the non-woven material in a continuous moving web. The web was carried on a heated moving belt which passed under a second heated moving belt, the two belts applying heat and compression to the coated web to fuse the bonding agent and the Celox powder to the web.

(29) Additionally a pressure roller was applied to smooth the surface of the granules to increase the bonding to the carrier material. The resulting material was smooth.

(30) The coated heat bonded web was then wound up to form a roll and the resulting material was cut into 5 cm5 cm squares, packaged and sterilised.

(31) A hole was made in the femoral artery of a 100 lbs swine using a 16 gauge needle. The wound bled severely. The material was applied to the wound site with finger pressure for 3 minutes. The bleeding was robustly stopped. After 3 minutes the material was removed from the bleeding area. The bleeding did not restart.

Example 3

(32) A granular haemostat (Celox) was bonded to a 1 mm thick polyurethane foam using a low melt copolyester resin with a melting range of 58-61 C. 40 gsm of resin was used, together with 40 gsm of Celox.

(33) The Celox powder and bonding agent granules were blended together and the combination powder then scatter coated onto the non-woven material in a continuous moving web. The web was carried on a heated moving belt which passed under a second heated moving belt, the two belts applying heat and compression to the coated web to fuse the bonding agent/Celox powder to the web.

(34) The coated heat bonded web was then wound to form a roll and the resulting material was cut into 5 cm5 cm squares, packaged and sterilised.

(35) A hole was made in the femoral artery of a 100 lbs swine using a 16 gauge needle. The wound bled severely. The material was applied to the wound site with finger pressure for 3 minutes. The bleeding was robustly stopped. After 3 minutes the material was removed from the bleeding area. The bleeding did not restart.

Example 4

(36) A granular haemostat (Celox) was bonded to a 120 gsm non-woven material using a low melt copolyester resin with a melting range of 58-61 C. 40 gsm of resin was used, together with 40 gsm of Celox.

(37) The Celox powder and bonding agent granules were blended together and the combination powder then scatter coated onto the non-woven material in a continuous moving web. The web was carried on a heated moving belt which passed under a second heated moving belt, the two belts applying heat and compression to the coated web to fuse the bonding agent/Celox powder to the web. The coated heat bonded web was then wound to form a roll.

(38) The roll was then passed back through the bonding machine and a further 40 gsm of resin and 40 gsm of Celox was applied to the other side of the fabric.

(39) The fabric now had two haemostatic surfaces. The resulting material was cut into 5 cmcm squares, packaged and sterilised.

Example 5

(40) A collagen haemostat was bonded to a 120 gsm non-woven material using a low melt copolyester resin with a melting range of 58-61 C. 40 gsm of resin was used, together with 40 gsm of dry collagen granules.

(41) The collagen and bonding agent granules were blended together and the combination powder then scatter coated onto the non-woven material in a continuous moving web. The web was carried on a heated moving belt which passed under a second heated moving belt, the two belts applying heat and compression to the coated web to fuse the bonding agent/Collagen powder to the web.

(42) The coated heat bonded web was then wound to form a roll. The resulting material was cut into 5 cm5 cm squares, packaged and sterilised.

(43) A hole was made in the femoral artery of a 100 lbs swine using a 16 gauge needle. The wound bled severely. The material was applied to the wound site with finger pressure for 3 minutes. The bleeding had slowed but did not totally stop initially. An additional material was reapplied for a further 2 minutes. The bleeding stopped. After 10 minutes the material was removed from the bleeding area. The bleeding did not restart.

Example 6

(44) An oxidised regenerated cellulose haemostat (ground up Surgicel) was bonded to a 120 gsm non-woven material using a low melt copolyester resin with a melting range of 58-61 C. 40 gsm of resin was used, together with 40 gsm of dry ORC granules.

(45) The ORC and bonding agent granules were blended together and the combination powder then scatter coated onto the non-woven material in a continuous moving web. The web was carried on a heated moving belt which passed under a second heated moving belt, the two belts applying heat and compression to the coated web to fuse the bonding agent/ORC powder to the web.

(46) The coated heat bonded web was then wound to form a roll. The resulting material was cut into 10 cm2 cm squares, packaged and sterilised.

Example 7

(47) An oxidised regenerated cellulose haemostat (ground up Surgicel) was bonded to a 120 gsm non-woven material using a meltable net (Delnet). 80 gsm of net was used, together with 40 gsm of Celox granules.

(48) The bonding net was laid on top of the carrier material and the granules then scatter coated onto the non-woven material in a continuous moving web. The web was carried on a heated moving belt which passed under a second heated moving belt, the two belts applying heat and compression to the coated web to fuse the bonding agent/Celox powder to the web.

(49) The coated heat bonded web can then be wound to form a roll. The resulting material was cut into 5 cm5 cm squares, packaged and sterilised.

Example 8

(50) The effectiveness of a haemostatic material according to the invention comprising Celox granules thereon was assessed by applying it to a vascular puncture site created with a 16 gauge needle in healthy Yorkshire swine.

(51) The material used was sheets of 1 cm1 cm and 4 cm4 cm in size, and only one sheet of it was applied to each vascular incision. FIGS. 7-10 show the wound and subsequent treatment using the haemostatic material of the invention. The suitability of each potential subject was confirmed before his or her acceptance.

(52) The following tables detail the procedure which was followed and the pre- and post-injury conditions of the test subjects.

(53) TABLE-US-00001 Prior Treatment 15 mins 1 hour Visual assessment x Measure blood pressure, etc x Photograph x Make wound x Apply haemostat x Apply compression x Video Treatment x Assess haemostasis x x x Remove Celox clot by hand x Irrigate to remove any residuals x Assessment of wound by expert x

(54) TABLE-US-00002 GENERAL Weight Age Body MAP over Method ID re-injury sex (kg) (weeks) Temp ( C.) 50 ml Hg Condition 1 cm 1 cm sheet 3 yes m 90-95 15-20 36.4 yes good 4 cm 4 cm sheet 4 yes m 90-95 15-20 37.6 yes good

(55) TABLE-US-00003 PRE-INJURY VITALS Body BP BP BP Heart rate Method ID Temp ( C.) MAP Systolic Diastolic BPM 1 cm 1 cm 3 36.4 96 103 72 76 sheet 4 cm 4 cm 4 37.2 63 98 74 69 sheet

(56) TABLE-US-00004 INJURY AND TREATMENT Bleed BP after Compression Method ID Wound type Time (s) Bleed Time treatment (mins) Haemo achieved? 1 cm 1 cm 3 Vascular 60 72 One 1 1 5 yes sheet incision cm sheet 4 cm 4 cm 4 Vascular 60 68 One 4 4 5 yes sheet incision cm sheet

(57) TABLE-US-00005 15 MINUTE ASSESSMENT body Heart Method ID assessment rebleed? temp ( C.) map Systolic Diastolic Rate BPM 1 cm 1 cm sheet 3 Alive no 34 84 113 69 50 4 cm 4 cm sheet 4 Alive no 33 92 104 76 60

(58) TABLE-US-00006 60 MINUTE/FINAL ASSESSMENT Body Heart Method assessment rebleed? temp ( C.) map Systolic Diastolic Rate BPM 1 cm 1 cm sheet 3 Alive no 34.4 83 108 64 54 4 cm 4 cm sheet 4 Alive no 32 76 96 58 51

(59) The assessment of haemostasis was made by visual assessment by data collection officers and confirmed with a trauma surgeon. A wound which is not haemostable (bleeding) after both 5 minutes compression and a further 2 min minutes compression counts as a failure. No adverse clinical events occurred during the assessment.

(60) The subjects survived the wounds. Only one sheet of the material of the invention was used on the wounds. No arterial re-bleeding was seen in the wounds.

(61) Haemostasis and Survival

(62) Haemostasis was assessed at the following points: 5 mins after initial compression 15 mins post compression

(63) No bleeding was seen from the wound at either time points. 100% haemostasis was achieved with all wounds on the pigs.

(64) Survival was recorded at the same points:

(65) 5 mins after initial compression 15 mins post compression

(66) The results clearly demonstrate that the haemostatic material of the invention is effective when applied to a vascular puncture site.

(67) It is of course to be understood that the present invention is not intended to be restricted to the foregoing examples which are described by way of example only.