Evaluation of Hemostatic Potential of Novel Absorbable Hemostatic Sponges Based on Chitosan and Pectin Natural Polymers by Thromboelastography

Uncontrolled hemorrhaging is the main cause of death due to military trauma and also in civilian settings. For use as surgical treatment, an ideal absorbable hemostatic dressing must be safe, rapidly effective, nonantigenic and show biocompatibility. Nowadays, a number of absorbable hemostatic dressings have been produced including porcine or bovine gelatin , collagen, regenerated oxidized cellulose. However, none of these dressings can claim to be the ideal solution, because of some notable adverse effects such as toxicity, potential infections and virus transfusion. Pectin and chitosan are natural, hydrophilic, biocompatible and biodegradable polymers with low toxicity.Pectin is an anionic polysaccharide, primarily composed of poly- D-galacturonic acid in which some of the residues are methylesterified. Chitosan is a cationic polysaccharide, derived by the deacetylation of chitin. This study reports the preparation of several collagen and pectin hemostatic sponges with controlled porosity, viscoelasticity and morphology.Thromboelastography analyses were performed using a Haemonetics TEG 5000 thromboelastograph with volunteers who were physically healthy and had no history of blood disorders. This analysis was used to acquire in vitro clotting parameters for total blood stabilized with sodium citrate (4% v/v) and exposed to the hemostatic materials evaluated. Firstly, 20 µL of 0.2 M aqueous CaCl₂ was added to 340 µL of the whole blood, followed by direct introduction of 0.5 mg of hemostatic sponges into the TEG sample cup containing the blood. Relevant parameters for the clotting process: R (time for formation of a clot with size of approximately 2 mm, and the beginning of fibrin production); K (time for the clot size to reach 20 mm); α angle (inclination between R and K, representing the rate of thrombin generation and the conversion of fibrinogen to fibrin); and MA (maximum amplitude, reflecting the maximum elastic property of fibrin and platelet adhesion) were measured.