Jeffrey F. Barletta, Alicia J. Mangram, Marilyn Byrne, Joseph F. Sucher, Alexzandra K. Hollingworth, Francis R. Ali-Osman, Gina R. Shirah, Michael Haley, James K. Dzandu

Augmented renal clearance (ARC) is common in trauma patients and associated with subtherapeutic antimicrobial concentrations. This study reported the incidence of ARC, identified ARC risk factors and described a model to predict ARC (i.e.,ARCTIC) that is specific to trauma patients. Consecutive trauma patients who were admitted to the ICU between March 2015 and January 2016 and had a measured creatinine clearance (CrCl) were considered for inclusion. Patients were excluded if their serum creatinine (SCr) was >1.3 mg/dL. ARC was defined as a measured CrCl ≥130ml/min. Demographic and trauma-specific variables were then compared and multivariate analysis was performed. Using these results, a weighted scoring system was constructed and evaluated using receiver operating characteristic (ROC) curve analysis. ARCTIC score cut-offs were chosen based on sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV). The derived scoring system was then compared to a previously published scoring system for accuracy. There were 133 patients with a mean age of 48±19 years and SCr of 0.8±0.2 mg/dL. The mean measured CrCl was 168±65 ml/min and the incidence of ARC was 67%. Multivariate analysis revealed the following risk factors for ARC [odds ratios (95% CI)]: age <56 [58.3(5.2-658.9), age 56 to 75 [13.5(1.2-151.7)], SCr<0.7mg/dL [12.5(3-52.6)] and male gender [6.9(1.9-24.9)]. Using these results, the ARCTIC scoring system was: 4 points if age <56, 3 points if age 57-75, 3 points if SCr <0.7 mg/dL and 2 points if male gender. ROC curve analysis revealed an area (95% CI) of 0.813(0.735-0.892), p<.001. An ARCTIC score of ≥ 6 had a sensitivity, specificity, PPV and NPV of 0.843, 0.682, 0.843 and 0.682, respectively. The incidence of ARC in trauma patients is high. The ARCTIC score represents a practical, pragmatic system that can be easily applied at the bedside. An ARCTIC score ≥6 represents an appropriate cut-off to screen for ARC where antimicrobial adjustments should be considered. Prognostic and epidemiologic study, level III.