1552. Correlation Between Vancomycin Serum Trough Concentrations and Area Under the Curve in Pediatric Patients

Abstract

BackgroundDespite years of experience with vancomycin (VAN), the optimal method to monitor VAN therapy in pediatric patients is still unknown. Recent pediatric data indicate serum trough concentrations lower than 10–20 mg/L or 15–20 mg/L based on indication may achieve an AUC24> 400 mg hours/L. The primary study objective was to compare AUC24 to goal VAN serum trough concentrations (STC).MethodsA retrospective chart review of pediatric patients who received intravenous VAN June 1, 2018 to December 31, 2018 was completed. AUC24 was calculated using a trapezoidal method with 2 steady-state serum concentrations. A serum peak concentration was drawn 1 hour and 15 minutes following the end of infusion and an STC was drawn 30 minutes prior to infusion.ResultsDuring 25 admissions, 12 patients had a first AUC24 at goal and 13 patients had a first AUC24 below goal. Of 41 AUC24 calculations, 27 AUC24s were ≥400 mg hours/L (group 1), and 14 AUC24s were <400 mg hours/L (group 2). Median AUC24 was 561 mg hours/L for group 1 vs. 344.5 mg hours/L for group 2 (P < 0.001). Correlating Cmin and Ctrough (Ctr) for group 1 and group 2 were 12 mg/L and 13.5 mg/L vs. 6.4 mg/L and 7.3 mg/L, respectively (P < 0.001). Figure 1 shows the pharmacokinetic parameters for each group. Spearman correlation between AUC24 and Cmin was 0.87. Of the 35 subtherapeutic VAN STCs, 20 (57.1%) achieved an AUC24 ≥400 mg hours/L (P = 0.08). Subgroup analysis of AUC24 400–600 mg hours/L showed a median AUC24 of 519 mg hours/L with correlating Cmin and Ctr of 10.6 mg/L and 11.9 mg/L, respectively. The MIC was <1 in 90.9% of cases (Figure 2). The mean VAN dose required to achieve an AUC24 ≥400 mg hours/L was 77.7 mg/kg/day; dosing frequency did not appear to affect AUC24 outcome. Time to culture clearance was 2 days in group 1 and 6.5 days in group 2 (P = 0.24). No cases of nephrotoxicity were identified despite AUC24 values ranging from 265–1294 mg hours/L.ConclusionAUC24 monitoring using a 2-sample trapezoidal method was successfully implemented at this institution. The results of this study align with previous pediatric studies, supporting the use of lower serum trough concentration goals of 10–15 mg/L. Disclosures All authors: No reported disclosures.