L. R. Copeland-Halperin1, J. Stodghill1, E. Emery1, A. W. Trickey1, J. Dort1 1Inova Fairfax Hospital,Surgery,Falls Church, VA, USA
Introduction: Bacteremia is a worrisome postoperative complication. While blood cultures (BCx) are routinely used to evaluate bacteremia, they are costly and may yield conflicting results. We previously reported on the relationship between BCx yield and the timing of culture collection after surgery. Here we present additional analyses of relationships between positive BCx and other cultures obtained concurrently to characterize surgical patients in whom postoperative blood cultures are most likely to identify pathogens.
Methods: Electronic medical records were reviewed for patients ≥18 years of age who had blood cultures drawn within 10 days after surgical procedures at a referral center in 2013. We collected demographic data and results of cultures of blood, urine, central and peripherally inserted venous catheters, respiratory secretions, wounds, and stool obtained within 24 hours of the highest postoperative temperature before postoperative day 10. Relationships between blood cultures and other culture results were assessed using chi-square tests, or Fisher’s exact tests when assumptions for chi-square were not met.
Results: A total of 1,804 cultures were identified; exclusion of contaminants left 1,780 cultures among 746 patients for analysis. Patients had a mean age of 59 years (range=18-95, SD=16.8). The majority were male (54%). Positive or indeterminate urine and respiratory cultures demonstrated statistically significant associations with positive blood culture results (Table 1). Patterns were similar for wound and stool cultures, but statistical power was limited for those comparisons. Overall, any positive or indeterminate culture increased the likelihood of positive blood culture (9.8% vs. 2.9%, odds ratio=3.58, p<0.001).
Conclusion: These findings from the largest series of its kind help identify clinical predictors associated with early postoperative bacteremia. Specifically, the presence of a positive or indeterminate urine, respiratory, wound, stool, or catheter tip culture significantly increased the likelihood of a positive blood culture.
