Inflammatory and Immune Responses to Surgery and Their Clinical Impact

Objective: The aim of this study was to describe current understanding of the local and systemic immune responses to surgery and their impact on clinical outcomes, predictive biomarkers, and potential treatment strategies. Background: Patients undergoing major surgery are at risk of life-threatening inflammatory complications that include infection, the systemic inflammatory response syndrome (SIRS), or sepsis. Although improvements in surgical technique and peri-operative care have resulted in reduction in the rates of these complications, they remain high, especially in patients undergoing complex abdominal procedures. There are currently no drugs licensed specifically for the treatment of sepsis nor is it possible to identify those at highest risk, which would allow pre-emptive therapy that may improve outcomes. Conclusions: Local immune responses to surgery lead to systemic proinflammatory and immunosuppressive phases that are temporally related and proportionate in magnitude. Improved understanding of these mechanisms has implications for clinical study design and has led to the emergence of novel biomarkers such as Toll-like receptor expression. These can be used to stratify patient care pathways to maximize the benefit from current therapies or to select the right target at the right phase of illness for future drug development.