Background: Sepsis remains a diagnostic challenge in the intensive care unit (ICU). The use of biomarkers in differentiating bacterial sepsis from other causes of systemic inflammatory syndrome (SIRS) may be particularly useful in the surgical population, given the systemic inflammatory response that often follows major surgery. The goal of this study was to assess test characteristics of a number of biomarkers for identifying ICU patients with a very low likelihood of bacterial sepsis.
Methods: A prospective cohort study was conducted in a surgical ICU of a university hospital. Patients with presumed bacterial sepsis were consecutively enrolled from February 2012 to April 2013. Concentrations of nine biomarkers (α-2 macroglobulin [A2M], C-reactive protein, ferritin, fibrinogen, haptoglobin, procalcitonin [PCT], serum amyloid A, serum amyloid P, and tissue plasminogen activator), were determined at baseline, 24 hours, 48 hours, and 72 hours after enrollment. The presence of bacterial sepsis was determined via medical record review by two infectious diseases trained physicians. Performance characteristics were calculated for varying combinations of biomarkers for discrimination of bacterial sepsis from other causes of SIRS.
Results: Of 69 patients meeting inclusion criteria, 42 (61%) had documented bacterial sepsis and 27 (39%) had other causes of SIRS. The most common sources of bacterial sepsis were bloodstream (33%), intra-abdominal (27%), and pulmonary (19%). A2M values were significantly lower at all measured timepoints in patients with bacterial sepsis (Figure 1a). Conversely, PCT values were significantly higher at all measured timepoints in patients with bacterial sepsis (Figure 1b). A number of combinations of A2M and PCT, using varying cutoff values and measurement timepoints, demonstrated moderately high negative predictive values (72%-75%) while retaining moderate specificities (46%-50%) for diagnosing bacterial sepsis.
Conclusion: Combinations of A2M and PCT demonstrated moderately high ability to discriminate bacterial sepsis from other causes of SIRS in surgical ICU patients. Future studies should focus on the use of these algorithms to improve antibiotic use in the critically ill surgical population.
S. Coffin, None
J. S. Gerber, None
C. Garrigan, None
X. Han, None
W. Bilker, None
J. Wise, None
P. Tolomeo, None
E. Lautenbach, None