Redefining the Systemic Inflammatory Response

From the first description of the "systemic inflammatory response" in the early 1990s, it has been recognized that this is a multifaceted response of the body to the combined insult of cardiothoracic surgery with bypass, involving causation by "activation of complement, coagulation, fibrinolytic, and kallikrein cascades, activation of neutrophils with degranulation and protease enzyme release, oxygen radical production, and the synthesis of various cytokines from mononuclear cells." Yet the intervening 15 years have seen a narrowing of research into individual systems and interventions naively targeted at single pathways without achieving clinically meaningful benefits. The time has come to redefine the systemic inflammatory response so that research can be more productively focused on objectively measuring and interdicting this multisystem disorder. A key concept of this new understanding is that translation into a hard adverse event occurs when the systemic imbalance is combined with a localized trigger. Triggers might be inadvertently provided by transient episodes of ischemia/malperfusion to vulnerable organs or handling trauma to major vessels. Future research should be directed at suppressing systemic activation with combinations of drugs and improved circuit coating, whereas changes in clinical practice and continuous monitoring of perfusion parameters can help eliminate localized triggering events.