(1452) Vancomycin in Critically Ill Patients Receiving Accelerated Venovenous Hemofiltration

Introduction: Accelerated venovenous hemofiltration (AVVH) is a hybrid renal replacement therapy modality offering higher hemofiltration rates with greater hemodynamic stability than intermittent hemodialysis. Renal replacement therapy affects antibiotic pharmacokinetics and pharmacodynamics, leading to uncertainty in efficacy and drug toxicity. The purpose of this study was to describe vancomycin dosing practices in patients receiving AVVH at an academic medical center, with the potential to model optimal vancomycin dosing and monitoring strategies.

Methods: This was a retrospective single-center analysis of vancomycin dosing strategies in critically ill adult patients receiving AVVH at an academic medical center. Patients were included if they received vancomycin while undergoing AVVH and had a vancomycin serum concentration measured within the first 24 hours of initiating concomitant vancomycin and AVVH. Major endpoint of this study was the incidence of in-range vancomycin levels (10-20 mcg/mL) in patients undergoing AVVH. Minor endpoints included vancomycin dosing and frequency, duration of AVVH session, and time from AVVH completion to vancomycin serum concentration obtainment.

Results: There were 285 patients screened, with 52 patients meeting the predetermined inclusion criteria. There were 79 unique AVVH sessions with an associated vancomycin level assessed. The median duration of AVVH session was 10.1 hours [IQR 9.5-12] and the median AVVH flow rate was 4000 mL/hr [IQR 4000-4000]. The incidence of in-range vancomycin levels was 68.4%. Median dose of vancomycin was 1250 mg [IQR 1000-1500] and 14.5 mg/kg [IQR 12.7-16.6] per each AVVH session. Median duration of vancomycin therapy at the time of patient being on both AVVH and vancomycin therapy was 2 days [IQR 1-7]. Median time from AVVH completion to vancomycin concentration obtainment was 2.8 hours [IQR 0.3-5.7] and the median time from vancomycin dose to serum concentration obtainment was 19.6 hours [15.4-23.1]

Conclusions: Majority of vancomycin levels collected were in-range using a median vancomycin dose of 14.5 mg/kg/dose. While this suggests most patients achieved in-range levels, additional prospective pharmacokinetic studies are needed to fully understand vancomycin exposure and dosing requirements during AVVH.