(979) Vancomycin AUC: MIC Versus Trough Monitoring in Patients Receiving CRRT

Introduction: Traditionally, targeting a vancomycin trough of 10-20 mcg/mL served as a surrogate for an area under the curve to minimum inhibitory concentration ratio (AUC:MIC) between 400-600 mg*h/L. AUC:MIC is now considered the optimal pharmacodynamic (PD) index to minimize drug exposure and maximize therapeutic effect. Continuous renal replacement therapy (CRRT) can alter vancomycin pharmacokinetics (PK) and PD, resulting in wide variability in vancomycin trough concentrations. Few studies have assessed the PK of vancomycin AUC:MIC monitoring in critically ill patients receiving CRRT. Thus, the goal of this study was to compare vancomycin AUC:MIC and trough monitoring in critically ill patients receiving vancomycin and CRRT.

Methods: This retrospective cohort study included patients receiving CRRT and vancomycin between September 2022 and March 2024. The primary outcome compared percentage of patients on vancomycin with therapeutic levels utilizing AUC:MIC monitoring to trough monitoring. Secondary outcomes included percentage of vancomycin AUC-derived troughs correlating with traditional trough goals, median daily dose of vancomycin required to achieve therapeutic levels and impact of CRRT rates on the vancomycin daily dose required to achieve therapeutic levels.

Results: A total of 65 patients were included with 36 and 29 patients in the AUC:MIC and trough groups, respectively. Patients with AUC:MIC monitoring were more likely to achieve therapeutic vancomycin levels compared to patients with trough monitoring (53% vs. 24%; p=0.024). In the AUC:MIC group, the median therapeutic AUC:MIC was 517 mg*h/L, with a median trough of 16.11 mcg/mL. Of the therapeutic AUC:MIC levels, only 52.6% correlated with traditional trough goals. In the trough monitoring group, the median therapeutic trough was 14.25 mcg/mL. There was no difference in the median vancomycin daily dose between the groups (14.9 mg/kg AUC:MIC vs. 15.9 mg/kg trough; p=0.203). Median CRRT rates between the therapeutic AUC:MIC and trough groups did not differ (2500 mL/hr vs. 2000 mL/hr, respectively; p=0.136).

Conclusions: This study suggests AUC:MIC monitoring is feasible and may be the optimal therapeutic drug monitoring technique in patients receiving vancomycin while on CRRT.