P70 Does meeting the clinical criteria for the systemic inflammatory response syndrome equate to biochemical inflammation following cardiac surgery

Introduction and Objectives The systemic inflammatory response syndrome (SIRS) criteria were developed in part as entry criteria for clinical trials of generalised inflammation from various causes. Despite being commonly used to assess inflammation in cardiac surgery, no one has evaluated whether the clinical defining criteria for inflammation equate to biochemical inflammation in this patient population. Our aim was to investigate whether the SIRS criteria equate to established biochemical indices of inflammation following cardiac surgery. Methods Retrospective analysis of prospectively collected data from an adult intensive care unit of a specialist cardiothoracic centre in the UK. 93 adult patients undergoing cardiac surgery admitted over a 34-month period between March 2004 and January 2007 were included. Patients were scored on the SIRS criteria from before to 72 h post-surgery. ELISAs were performed on archived plasma samples taken before surgery and at 4, 24, 48 and 72 h post-operatively to determine concentrations of IL-1s, IL-1RA, IL-6, IL-8, IL-10, myeloperoxidase (MPO) and C reactive protein (CRP). Results Significantly elevated levels of all inflammatory indices were detected post-operatively with the exception of IL-1s. Patients meeting SIRS criteria demonstrated higher levels of IL-6, IL-1RA and CRP compared to those who did not meet the criteria. An absence or only weak correlation was found between SIRS and mass of biomarker. Conclusions The clinical defining criteria for inflammation (SIRS criteria) do not equate to established biochemical indices of inflammation in cardiac surgery patients; hence the criteria alone should not be used to assess inflammation in this patient population.