Experimental study of intraparenchymal fibrinogen and topical thrombin to seal pleural defects

Objective: Fibrin sealants are used to close surgical pleural defects, but may detach, causing a postoperative air-leak. We investigated a new means of applying fibrin glue for closing pleural defects. Methods: Pleural defects (10-mm and 4-mm diameters, respectively) were created in swine and rats via thoracotomy. They were sealed by a) injection of a fibrinogen solution into the lung parenchyma after instillation of a thrombin solution onto the pleural defect (group A), b) fibrinogen and thrombin spray (group B), c) fibrinogen instillation and a thrombin-dipped polyglycolic acid sheet (group C), or d) fibrin glue-coated collagen fleece (group D). Resistance to airway pressure was compared and the sealed areas were histologically examined. Results: In group A, the minimum seal-breaking airway pressure was consistently > 40 cmH₂O, versus 37.2 ± 3.6 cmH₂O in group B, 37.2 ± 4.0 cmH₂O in group C, and 39.0 ± 1.7 cmH₂O in group D, which was statistically significant. Histologically, the fibrin layer infiltrated the lung parenchyma and covered the defect in group A, but not in the other groups. Conclusions: The intraparenchymal injection of fibrinogen combined with instillation of thrombin created an effective fibrin layer associated with early pleural regeneration that reliably prevented pleural air leaks.