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The lack of established cause and effect between putative mediators of inflammation and adverse clinical outcomes has been responsible for many failed anti-inflammatory interventions in cardiopulmonary bypass (CPB). Candidate interventions that impress in preclinical trials by suppressing a given inflammation marker might fail at the clinical trial stage because the marker of interest is not linked causally to an adverse outcome. Alternatively, there exist examples in which pharmaceutical agents or other interventions improve clinical outcomes but for which we are uncertain of any antiinflammatory mechanism. The Outcomes consensus panel made 3 recommendations in 2009 for the conduct of clinical trials focused on the systemic inflammatory response. This panel was tasked with updating, as well as simplifying, a previous consensus statement. The present recommendations for investigators are the following: (1) Measure at least 1 inflammation marker, defined in broad terms; (2) measure at least 1clinical end point, drawn from a list of practical yet clinically meaningful end points suggested by the consensus panel; and(3) report a core set of CPB and perfusion criteria that maybe linked to outcomes. Our collective belief is that adhering to these simple consensus recommendations will help define the influence of CPB practice on the systemic inflammatory response, advance our understanding of causal inflammatory mechanisms, and standardize the reporting of research findings in the peer-reviewed literature.

The causal factors of the systemic inflammatory response to cardiopulmonary bypass (CPB) were correctly identified in the early 1990 s: "... 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" [Butler 1993]. Why therefore have clinical advances to curb the systemic inflammatory response proven such a disappointment? Part of the problem is that cardiac surgery has never taken intellectual ownership of this issue, borrowing its diagnosis from critical care medicine and failing to define the minimal criteria that should be measured when reporting on the systemic inflammatory response. An evidence based review of the current literature by many of the coauthors on this paper found that the majority of studies on the systemic inflammatory response did not measure a single one of the causal factors listed above - thus hindering our ability to identify mechanisms of causation and identify drug targets [Landis 2008]. A panel of experts convened at the Outcomes XII meeting, Barbados 2008, drafted the present consensus document in order to provide a framework to guide future studies and interdictions of the systemic inflammatory response. Herein, we have recommended: 1) mandatory reporting of minimal CPB and perfusion criteria that may affect outcomes, 2) reporting of a minimal set of causal inflammatory markers linked to adverse sequelae, and 3) reporting of at least one clinical end-point of organ injury, from a list of endpoints and markers of organ injury that balance practicality with clinical meaningfulness. It is our collective belief that this document will serve as a foundation for furthering our understanding of the influence of CPB practice with the systemic inflammatory response by standardizing the reporting of research findings in the peer-reviewed literature.