Screening for Bacteremia in Trauma Patients: Traditional Markers Fall Short

Abstract

Background Deranged physiology in trauma complicates the clinical identification of sepsis, resulting in overscreening for bacteremia. No clinical signs or biomarkers accurately diagnose sepsis in this population. Our objective was to evaluate the accuracy of the current criteria used to prompt screening for bacteremia in trauma patients and determine independent predictors of bacteremia. Materials and Methods Adult trauma patients admitted to our level I academic trauma center who had blood cultures (BCs) drawn were identified. Those with positive BCs were compared to those with negative or false positive BCs. False positive was defined as a BC deemed contaminated and not treated at the discretion of the attending physician. Results Over a 2-year period, 366 trauma patients had BCs drawn. After excluding surveillance cultures (those drawn to demonstrate bacteremia clearance), 492 unique BC sets were evaluated; 104 (21.1%) BC sets were positive; 30 (28.8%) of these were falsely positive, resulting in a true-positive rate of 15% in the screened population. Univariate analysis suggested temperature and heart rate were associated with positive BC, while multivariable analysis found only the presence of a central line and lactic acid to be predictive. Procalcitonin (PCT) was poorly predictive, with a positive predictive value of 18% and a negative predictive value of 91%. Conclusion Current tools for identifying bacteremia in trauma patients result in overscreening. PCT may have a limited role as a negative predictor for bacteremia. Given that false-positive BCs have negative patient and economic consequences, future study should focus on development of alternative screening modalities.

Fever and infections in surgical intensive care: an American Association for the Surgery of Trauma Critical Care Committee clinical consensus document

“…Procalcitonin has been shown to significantly reduce antibiotic use for lower respiratory infections without adversely impacting outcome. 51 52 It has a high negative predictive value of 91% 40 and follow-up levels have been shown useful for antibiotic discontinuation, 18 however, caution is advised in circumstances that raise procalcitonin at baseline such as trauma including surgical trauma, and inflammatory conditions, like pancreatitis. There is no standard recommended use of procalcitonin in the critically ill trauma population.…”

“…Routine repeat blood cultures to assess clearance of bacteremia are usually not needed except if the patient does not clinically improve or if they are at risk for metastatic infections (eg, Staphylococcus aureus). [39][40][41] Blood cultures can be considered if the risk to the patient is high if a bacteremia is missed (eg, in a patient with a pacemaker and cellulitis). 39 Regarding culturing methods, separate fungal cultures are not needed because most Candida species grow better in normal culture media.…”