A comparison of chitosan and collagen sponges as hemostatic dressings

The hemostatic capability, adhesion ability and biocompatibility of chitosan sponges were compared with commercial collagen sponges. The chitosan sponges were briefly immersed in an aqueous 20% ammonia solution before being applied to a rabbit cervical vein wound. The total amount of bleeding from the injured veins until hemostasis was similar for both chitosan and collagen sponges. The complete hemostasis success rates for both the chitosan and collagen sponges were also similar. Under hemostasis, the chitosan sponges strongly adhered to the surface of the rabbit muscles, whereas the collagen sponges were easily detached from the muscles. Under wet conditions, however, there was no significant difference in the adhesive ability between the two sponges. During implantation, the chitosan sponges were much more flexible and resistant to breakage than the collagen sponges. The biocompatibilities and biodegradation rates of the two sponges were totally different after subcutaneous implantation in rabbits. The chitosan sponge was degraded much slower than the collagen sponge, while tissue responses for the chitosan sponges were much greater than for the collagen sponges.