The systemic inflammatory response to anaesthesia and surgery

Major surgery or trauma induces a systemic inflammatory response syndrome (SIRS). In this review the response to uncomplicated surgery is described. The inflammatory response consists of hormonal, metabolic, and immunological components. The extent of the inflammatory response correlates with the magnitude of the surgery or tissue injury. After uncomplicated major surgery a delicate balance between pro- and anti-inflammatory mediators is observed. When the injury is severe, an exaggerated response might develop and the condition progresses to organ dysfunction. In cases where patients are exposed to several events in the form of trauma and surgery immune paralysis may develop. This is associated with increased risk of infection and sepsis. The effect of anaesthetics on the inflammatory response has been studied extensively in vitro, but to a lesser extent in vivo. However, the immunosuppressive effects of anaesthetics appear to be negligible compared to the effect of the surgical trauma.