Fibrin sealants are blood-derived products that are absorbable and form fibrin clots to arrest bleeding during surgeries. Fibrin clots are formed when thrombin activates fibrinogen in the presence of certain clotting factors. Fibrin sealants should only be applied on dry surfaces and on oozing wounds. Profusely bleeding wounds would be too moist to establish a good seal. Fibrin sealants are used in a wide range of procedures including cardiac, vascular, lung, liver, reconstructive plastic, oral and maxillofacial surgery. More urologic and renal applications are also being reported. Thrombin and fibrinogen are either taken from the patient’s own blood (autologous) or from a pool of human donors (homologous). For the purpose of this research report, fibrin sealants in this section only refer to the liquid fibrin products and not the fibrin patches. The fibrin patches are considered under the combination hemostats category, due to the stark difference between the liquids and patches in terms of price, efficacy, ease of use, complexity in product preparation and other characteristics.
Protein-based sealants are generally used to seal large vessels and in anastomoses. They can be used as an adjunct to sutures and staples and have a tensile strength that is up to five times stronger than a bond made from fibrin sealants. Containing purified bovine serum albumin (BSA) and glutaraldehyde, these sealants are dispensed from a double barreled syringe. The two components mix at the tip of the syringe and are covalently bonded to each other to form a strong seal, independent of the body’s clotting cascade. The seal polymerizes in 30 seconds and reaches its bonding strength in 2 minutes.
Synthetic Tissue Sealants
Polyethylene glycol (PEG) can be combined with synthetic peptides and protein polymers to form synthetic tissue sealants. When the monomers link, they form a bond or seal that can be used to prevent leakage of fluids, gases or solids. New synthetic tissue sealants consisting of a blend of two monomers, octyl cyanoacrylate (2-OCA) and butyl lactoyl cyanoacytate (BLCA) have recently entered the market. Synthetic tissue sealants are ideal for vascular, pulmonary and gastrointestinal surgeries. Free of protein, human products and animal products, synthetic sealants pose no risk of transmitting disease, developing antibody resistance or causing infection.