Optimized thrombin dilution protocol for a slowly setting fibrin sealant in surgery

Abstract

BACKGROUND: Fibrin sealants find applications in many surgical fields (e.g., plastic and reconstructive surgery) where a slower setting time of about 30 to 60 s is beneficial. This can be achieved by diluting the thrombin component of the fibrin sealant to a concentration of about 5 IU/ml. This work was carried out to define an optimal dilution medium for thrombin which maintains all relevant functional parameters of the fibrin sealant and which is easy to prepare with components available in most operating theaters. METHODS: Different performance criteria of a fibrin sealant were tested in vitro by the following methods: adhesive strength in a rat skin adhesion model, turbidimetry and scanning electron microscopy to determine the fibrin clots structure, tensile strength of the fibrin clots by measuring the force at break. The cross-linking of the fibrin sealant by factor XIII (FXIII) as a function of the calcium concentration was assessed by quantitative electrophoresis. RESULTS: A dilution medium containing only calcium chloride in a concentration of about 20 mM performed best in most of the applied test systems. Dilution media with high ionic strength resulted in clots with low adhesive and tensile strength, thin fibrin fibers, and low clot elasticity. Dilution media without calcium prevented proper cross-linking of the resulting fibrin clots and led to clots with low tensile and adhesive strength. CONCLUSIONS: We present an optimized simple dilution protocol for the dilution of the thrombin component for a slowly setting fibrin sealant.