Comparison of hemostatic dressings for superficial wounds using a new spectrophotometric coagulation assay.

Due to demographical changes the number of elderly patients depending on oral anticoagulation is expected to rise. Prolonged bleeding times in case of traumatic injuries represent the drawback of these medications, not only in major trauma, but also in superficial wounds. Therefore, dressings capable of accelerating coagulation onset and shortening bleeding times are desirable for these patients. The hemostatic potential and physical properties of different types of superficial wound dressings (standard wound pad, two alginates, chitosan, collagen (Lyostypt(®)), oxidized cellulose, and QuikClot(®)) were assessed in vitro. For this purpose the clotting times of blood under the influence of the named hemostatics from healthy volunteers were compared with Marcumar(®) or ASS(®) treated patients. For that, a newly developed coagulation assay based on spectrophotometric extinction measurements of thrombin activity was used. The fastest coagulation onset was observed for oxidized cellulose (Ø 2.47 min), Lantor alginate-L (Ø 2.50 min) and QuikClot(®) (Ø 3.01 min). Chitosan (Ø 5.32 min) and the collagen Lyostypt(®) (Ø 7.59 min) induced clotting comparatively late. Regarding physical parameters, QuikClot(®) showed the lowest absorption capacity and speed while chitosan and both alginates achieved the highest. While oxidized cellulose displayed the best clotting times, unfortunately it also revealed low absorption capacity. All tested specimens seem to induce clotting independently from the administered type of oral anticoagulant, providing the possibility to neglect the disadvantage in clotting times arising from anticoagulation on a local basis. QuikClot(®), oxidized cellulose and unexpectedly alginate-L were superior to chitosan and Lyostypt(®). Due to its additional well-known positive effect on wound healing alginate-L should be considered for further investigations.