Arianna Vidger, PharmD,
Clinical Pharmacy Specialist - Critical Care
Indiana University Health Methodist Hospital
Indianapolis, Indiana
Disclosure information not submitted.
Laura Aykroyd, PharmD, BCPS
Clinical Pharmacy Specialist, Neurocritical Care
IU Health Methodist Hospital, United States
Disclosure information not submitted.
Emily Miller, BCPS, PharmD, FCCM
Clinical Pharmacy Specialist, Trauma/Adult Critical Care
Indiana University Health Methodist Hospital, United States
Disclosure information not submitted.
Lori Wetmore, PharmD, BCPS
Clinical Pharmacy Specialist, Neurocritical Care
Indiana University Health, United States
Disclosure information not submitted.
Title: Sub-Therapeutic Vancomycin Levels and Augmented Renal Clearance in Neurocritical Care Patient
Introduction/Hypothesis: Augmented renal clearance (ARC) is a phenomenon frequently observed in neurocritical care (NCC) patients and may increase risk of sub-therapeutic vancomycin levels. The goal of this study was to evaluate rates of sub-therapeutic vancomycin levels and ARC in NCC patients and compare them to non-neuro ICU patients.
Methods: This retrospective observational study included adult ICU patients receiving vancomycin with at least 1 trough level between 2018-2019. Patients with AKI on admission or vancomycin initiation, non-neuro trauma, mistimed levels, or transfer from an outside hospital or non-ICU unit to ICU were excluded. Patients admitted to NCC units for primary neurologic disease processes were included in a 1:1 ratio with patients admitted to non-NCC units for non-neurologic reasons. The primary endpoints were rate of sub-therapeutic vancomycin level and rate of ARC. Sub-therapeutic vancomycin levels were defined as < 15 mcg/mL for central nervous system (CNS) indications and < 10 mcg/mL for non-CNS indications. ARC was defined as estimated creatinine clearance >130 mL/min based on Cockcroft-Gault.
Results: One hundred seventy-six patients were included, with 88 patients in each group. Patients in the NCC group were younger (median age 41 v. 58, p >0.001), more likely to be male (73% v. 49%, p=0.001), and more likely to be treated for CNS indications (44% v. 1%, p< 0.001). Patients in the NCC group were more likely to have a sub-therapeutic level (68% v. 33%, p< 0.001) despite higher total daily doses, and were more likely to experience augmented renal clearance at the time of the level (70% v. 43%, p< 0.001). Significant differences between predicted and measured vancomycin levels were more frequently observed in the NCC group v. the non-NCC group. In a multiple logistic regression analysis, younger age, higher actual body weight, lower admission serum creatinine, and male gender were associated with higher rates of ARC.
Conclusions: In critically ill patients without baseline renal dysfunction, NCC patients were more likely to have sub-therapeutic vancomycin levels and experience augmented renal clearance than non-neuro ICU patients, likely influenced by differences in baseline patient characteristics. Risk factors for ARC should be considered when selecting initial regimens to avoid under-dosing.