Investigation of the appropriate viscosity of fibrinogen in repairing pleural defects using ventilation and anchoring in an ex vivo pig model

Our previous study revealed that the viscosity of fibrinogen could influence the effectiveness of ventilation and anchoring (V/A) methods for controlling air leakages. Here, we examined the association between the viscosity of fibrinogen and effectiveness using an ex vivo pig model. The fibrin glue used in this study was BOLHEAL® (KM Biologics Co., Ltd., Kumamoto, Japan). We prepared three types of fibrinogen with different viscosities (higher and lower than normal), including one without additives. Using an ex vivo pig model, a pleural defect was made, and the defect was repaired using three different viscosities of fibrinogen through the V/A method. We measured the rupture pressure at the repair site (N = 10) and histologically evaluated the depth of fibrin infiltration into the lung parenchyma at the repair sites. The median rupture pressure was 51.5 (40–73) cmH2O in Group 1 (lower viscosity), 47.0 (47–88) cmH2O in Group 2 (no change in viscosity), and 35.5 (25–61) cmH2O in Group 3 (higher viscosity). There was no statistically significant difference between Groups 1 and 2 (p = 0.819), but the rupture pressure was significantly higher in Group 2 than in Group 3 (p = 0.0136). Histological evaluation revealed deep infiltration of fibrin into the lung parenchyma in Groups 1 and 2, but no such infiltration was observed in the higher-viscosity group. The results of this experiment suggested that the V/A method using fibrin glue containing low-viscosity fibrinogen was more effective in controlling air leakage due to pleural defects.