A standardized animal model for evaluation of hemostatic effectiveness of various materials.

Two anatomic sites of bleeding injuries were selected in dogs to evaluate the hemostatic effectiveness and handling properties of various hemostatic materials. Split-thickness skin excisions inflict a wound of 90 cm2 area with regular spotted bleeding, which allows gravimetric quantitation of blood loss and of ease of removal of the agent. Excision of a wedge of the spleen 0.5 cm deep and 4 cm wide induced reproducible and moderate bleeding in pentobarbital-anesthesized dogs. Three to four similar injuries could be inflicted in the same spleen with comparable blood flow. In this model of bleeding injury only the highly effective hemostatic agents based on collagen and with a sheet-like structure successfully stopped the bleeding within 3 minutes. Powder-like collagen was effective only when pressed against the wound. Gelatin sponge or oxidized cellulose materials were less effective.