Evaluating perfusion and metabolic responses of microvascular free flaps to ischemia, reperfusion and fluid resuscitation during septic shock in a large animal model
摘要
Microvascular free flap transfer is an essential procedure in head and neck reconstructive surgery, with total flap loss representing the primary complication. Sepsis has been identified as a critical risk factor contributing to flap failure. Here we aimed to evaluate the impact of septic shock on free flap vitality using a large animal model and further investigated the flap-specific effects of different fluid resuscitation strategies on flap viability and metabolic response. A prospective, randomized trial was conducted on 31 juvenile male pigs to assess the effects of 3 fluid resuscitation strategies following septic shock induced by lipopolysaccharide infusion. The strategies included a balanced crystalloid solution, a colloid, and a combination of crystalloid and resveratrol. Free flap vitality was continuously monitored using hyperspectral imaging and blood gas analysis, comparing intraflap venous blood with central venous blood. The crystalloid group most effectively maintained higher oxygen saturation and lower lactate levels. Conversely, the colloid group exhibited lower tissue oxygen saturation and higher lactate levels. The combination of crystalloid and resveratrol stabilized the hemoglobin and tissue water indices. The study demonstrated a significant influence of different fluid resuscitation strategies on metabolic and perfusion outcomes of free flaps under septic conditions. Administration of crystalloid suggests optimized oxygen delivery and utilization, whereas the combination with resveratrol provided an improved balance of blood volume and hydration, hence preventing fluid overload.