The role of hydrogen peroxide in intra operative wound preparation based on an in-vitro fibrin clot degradation model

Abstract Three per cent hydrogen peroxide (H2O2) is widely used to irrigate acute and chronic wounds in the surgical setting and clinical experience tells us that it is more effective at removing dried-on blood than normal saline alone. We hypothesise that this is due to the effect of H2O2 on fibrin clot architecture via fibrinolysis. We investigate the mechanisms and discuss the clinical implications using an in vitro model. Coagulation assays with normal saline (NaCl), 1% and 3% concentrations of H2O2 were performed to determine the effect on fibrin clot formation. These effects were confirmed with spectrophotometry. The effects of 1%, 3% and 10% H2O2 on the macroscopic and microscopic features of fibrin clots were assessed at set time intervals and compared to a NaCl control. Quantitative analysis of fibrin networks was undertaken to determine fibre length, diameter, branch point density and pore size. Fibrin clots immersed in 1%, 3% and 10% H2O2 demonstrated volume losses of 0.09-0.25mm3/min whereas those immersed in the normal saline gained in volume by 0.02±0.13 mm3/min. Quantitative analysis showed that H2O2 affects the structure of the fibrin clot in a concentration dependent manner, with increasing fibre length, diameter and consequently pore sizes. Our results support our hypothesis that the efficacy of H2O2 in cleaning blood from wounds is enhanced by its effects on fibrin clot architecture in a concentration and time dependent manner. The observed changes in fiber size and branch point density suggest that H2O2 is acting on the quaternary structure of the fibrin clot, most likely via its effect on cross-linking of the fibrin monomers and may therefore be of benefit for the removal of other fibrin dependent structures such as wound slough.