Fibrin Sealant (EVICEL®)

Various electrosurgical instruments are available and are used for dissection and sealing vascular structures, while topical hemostatic agents, including fibrin sealants, are used to manage bleeding from surfaces or cavities that are not amenable to suturing, electrosurgery, or other specialized instruments (eg, argon plasma coagulator). Fibrin sealants are a two-component system comprised of a solution of concentrated fibrinogen and factor XIII that is combined with a solution of thrombin and calcium to form a coagulum. Once combined, a fibrin clot forms in seconds, or somewhat more slowly if a more diluted form of thrombin is used. Because fibrin sealants have fibrinogen concentrations that are higher than physiologic concentrations at the site of bleeding (particularly for commercial preparations), clot formation with fibrin sealants is faster than the native coagulation process . The contribution of flow to clot retraction was discovered using a microfluidic device capable of flowing human blood over a side channel plugged with collagen . This device was used in one study to measure thrombus permeability and contraction in the presence of platelet binding to collagen alone or in the presence of thrombin and fibrinogen. Collagen supported formation of a 20-micrometer thick platelet layer, which retracted significantly upon cessation of flow but resulted in a 5.34-fold increase in permeability because of reconfiguration of the supporting collagen. The presence of thrombin and fibrinogen allowed isotropic contraction of platelets, creating an impermeable clot. Although not the purpose of this study, these results would seem to predict that applying a combination of thrombin and fibrinogen promotes a more hemostatic clot than using a collagen alone as a mechanical barrier to flow. The use of fibrin sealants is reviewed here. The use of other topical hemostatic agents and tissue adhesives or sealants, including topical thrombin as a single-component topical agent, is discussed separately <a id="