1445: VANCOMYCIN DOSING IN PATIENTS RECEIVING SHIFT RENAL REPLACEMENT THERAPY

Abstract

Learning Objectives: SHIFT therapy is a type of renal replacement therapy (RRT) used as an alternative to conventional intermittent hemodialysis (iHD) in intensive care unit (ICU) patients being transitioned from continuous RRT as they become more hemodynamically stable. SHIFT therapy is performed over 6-12 hours. The scarcity of evidence on drug dosing with SHIFT could lead to overdosing or underdosing antimicrobials used to treat potentially life threatening infections. The purpose of the study is to describe and provide optimal vancomycin dosing regimens for patients receiving SHIFT therapy. Methods: This retrospective cohort study evaluated patients consecutively admitted to the Medical-Surgical ICU at the Medical University of South Carolina between October 2017 and June 2018. It included patients who received intravenous (IV) vancomycin while on SHIFT therapy. The primary outcome was percent reduction in serum vancomycin concentration post-SHIFT therapy. The secondary outcome was post-SHIFT vancomycin serum concentrations within therapeutic range (15-20 mcg/ml). Results: Nine patients with a total of16 vancomycin administrations were included in the study, of which 4 patients with 5 vancomycin administrations had both preand post-SHIFT serum vancomycin concentrations. The median (IQR) vancomycin dose was 14.4 mg/kg (13.7-17.9 mg/kg). The highest dialysate flow rates of 77.7 and 86.4 ml/kg/hr reduced serum vancomycin concentrations by 45% and 50%, respectively, while the lowest dialysate flow rate of 14.8 (ml/kg/hr) reduced serum vancomycin concentration by only 21%. Total daily SHIFT dialysate volumes (ml) of 12000, 36000, 40000, 40000, and 60000 reduced serum vancomycin concentrations by 21%, 45%, 36%, 50%, and 35%, respectively. Only 9 of the 16 vancomycin administrations resulted in therapeutic post-SHIFT levels, median (IQR) 17.6 mcg/ml, 15.6-22.4 mcg/ml, however pre-SHIFT serum concentrations were variable. Conclusions: As higher dialysate flow rates were associated with greater reductions in serum vancomycin concentrations, flow rates should be taken into consideration when dosing IV vancomycin in patients receiving SHIFT therapy. Additional studies are warranted to investigate how SHIFT therapy flow rates impact vancomycin clearance.