Severe sepsis and systemic inflammatory response syndrome in emergency department patients with suspected severe infection.

Background: Severe sepsis is a common condition with a reported high mortality, but most studies have been confined to intensive care unit (ICU) populations. The systemic inflammatory response syndrome (SIRS) has been used to define sepsis, however its usefulness has been questioned. Our aim was to describe the prevalence and clinical impact of severe sepsis and SIRS in patients admitted from the emergency department (ED) with a suspected serious infection. Methods: Four hundred and four adult patients were enrolled prospectively from the ED. Variables defining severe sepsis and SIRS were measured and the relationship between severe sepsis, SIRS, and the clinical course was analyzed. Results: Infections were diagnosed in 344 patients (85%). The overall mortality rate at 28 days was 2.7%, and 4.5% of patients were treated in the ICU. Patients with severe sepsis within 24 h of admission (42%) were more likely to suffer a critical course (ICU admission 9.0%, death 5.1%; p < 0.001). While SIRS was observed in 72% of the subjects at presentation, it was not associated with severe sepsis within 24 h or a subsequent critical course. Furthermore, 23% of patients with severe sepsis within 24 h did not present with SIRS. Conclusions: Severe sepsis was a common condition among ED patients with a clinically suspected serious infection. Mortality was low compared with results from the ICU setting, suggesting that severe sepsis is a more benign disease than earlier reported. As a tool for the definition of sepsis and for the selection of patients for clinical sepsis trials, SIRS lacks acceptable discriminative ability in an ED population with a high prevalence of serious infections.