Evaluation of Pharmacodynamic Target Attainment With Vancomycin Treatment of Infections Due to Staphylococcus Aureus

Study Design: This is a prospective cohort study with a retrospective chart review component.

Inclusion and Exclusion Criteria: Inpatients of The Nebraska Medical Center will be included if they are 19 years of age or older, prescribed intravenous vancomycin therapy with a dosing interval of 24 hours or less, and therapy is continued for at least 3 doses or five half lives. Exclusion criteria consists of an estimated creatinine clearance less than 30 ml/min, concurrent use of dialysis, and pregnancy.

Interventions: For the prospective component eligible patients will be consented and enrolled. A vancomycin trough level will be determined as normal standard of care thirty minutes prior to the appropriate vancomycin dose, followed by a vancomycin peak level one hour after the end of the infusion. Serum concentration time data will then be used to calculate an AUC. The retrospective component of the study will involve a chart review of patients treated with vancomycin in which a serum trough and peak level was obtained and calculation of the AUC as described.

Evaluations: Serum concentration time data will be used to calculate an AUC for each patient enrolled in the study and from all charts reviewed that meet criteria. MIC data will be determined for Staphylococcus aureus isolates obtained from The Nebraska Medical Center. The two sets of data will then be used to calculate an AUC:MIC ratio. The AUC:MIC data will be compared to the goal ratio of greater than 400. Additionally, using the AUC data from our patients and the MICs derived from a large national surveillance data base, a Monte Carlo analysis will be completed to determine the probability of achieving therapeutic ratios.