Early Monocyte Chemoattractant Protein-1 Elevation Predicts Surgical Site Infections after Blunt Trauma

Dysregulation of the inflammatory and immune response to injury may increase susceptibility to secondary infections after trauma. It is unknown whether cytokines involved in this response could function as plasma biomarkers for surgical site infection (SSI). We hypothesized that the early cytokine response differs between patients who develop SSI and those who do not and that critical cytokine threshold values could be used to predict risk of SSI. Using the Glue Grant database, we performed an analysis of severely injured blunt trauma patients who underwent a major procedure and had available cytokine data. Patients were divided into SSI and no SSI groups. Receiver operating curve analysis was used to determine acceptable early cytokine predictors of SSI and critical threshold values. Multivariable regression analysis was then performed to determine the odds of developing SSI using threshold values, adjusting for key patient or injury factors. Cytokine levels were compared between SSI and no SSI groups at three time points. The study cohort consisted of 70 patients and 11 patients developed SSI. Monocyte chemoattractant protein-1 (MCP-1) was the only acceptable early predictor of SSI with an area under the curve (AUC) of 0.71 (p = 0.03) and a critical threshold value of 490 pg/mL. Monocyte chemoattractant protein-1 levels above this threshold within 24 hours of injury were associated with SSI (adjusted odds ratio [AOR] 8.1; p = 0.01). Monocyte chemoattractant protein-1 levels within 24 hours of injury were higher in those who developed SSI (994 vs. 259 pg/mL; p < 0.01) and remained higher in the SSI group at 33 hours from injury (338 vs. 144 pg/mL; p = 0.01), but were similar by 106 hours (155 vs. 97 pg/mL; p = 0.19). Among cytokines involved in the early response to trauma, only early elevation of MCP-1 predicted SSI after blunt trauma. Monocyte chemoattractant protein-1 may act as a specific and early marker for SSI after blunt trauma, allowing for preventative measures to mitigate risks.