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 by 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 the 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 the increase in 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 fibre 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.

Keywords: Wound irrigation; coagulation assay; fibrin clot; fibrinolysis; hydrogen peroxide.