title: Weight-based versus set dosing of vancomycin for coronary artery bypass grafting or aortic valve surgery.
abstract: OBJECTIVE
  This study was undertaken to identify a preferred dosing strategy for patients undergoing coronary artery bypass grafting or valve replacement procedures with cardiopulmonary bypass.
  
  
  METHODS
  Patients undergoing coronary artery bypass grafting, valve replacement surgery, or both were randomly assigned to receive either standard 1-g dosing with vancomycin before and after cardiopulmonary bypass or a single weight-based 20-mg/kg dose before surgery. The primary outcome was the percentage of time plasma concentrations were greater than 15 μg/mL during cardiopulmonary bypass and at surgical closure. Secondary outcomes included concentration of vancomycin in endothoracic tissue after vancomycin infusion, average time patients had vancomycin concentrations greater than 15 μg/mL, and vancomycin plasma and tissue pharmacokinetic parameters.
  
  
  RESULTS
  Baseline characteristics were similar between the study dosing group (n = 10) and the standard dosing group (n = 10). From postinfusion to end of bypass, the median percentage of time vancomycin concentrations remained greater than 15 μg/mL was 100% (interquartile range [IQR], 72.6%-100%) for weight-based dosing versus 43.7% (IQR, 28.7%-53.4%) for standard dosing (P = .0005). From postinfusion to surgical closure, the percentage of time vancomycin concentrations remained greater than 15 μg/mL was significantly higher in the weight-based group (100% [IQR, 58.3%-100%] vs 34.6% [IQR, 25.3%-41.6%]; P = .0005). Weight-based dosing increased calculated time with vancomycin concentrations greater than 15 μg/mL and resulted in higher endothoracic tissue vancomycin concentrations.
  
  
  CONCLUSIONS
  Weight-based vancomycin dosing before coronary artery bypass grafting or valve replacement results in vancomycin concentrations greater than 15 μg/mL consistently more than does standard 1-g dosing.
authors: University of Washington Medical Center, Seattle, Wash.
authors: Matthew J
authors: MJ
authors: Hafermann
authors: University of Colorado Hospital, Aurora, Colo; Department of Clinical Pharmacy, University of Colorado Skaggs School of Pharmacy and Pharmaceutical Sciences, Aurora, Colo. Electronic address: Ty.Kiser@ucdenver.edu.
authors: Tyree H
authors: TH
authors: Kiser
authors: University of Colorado Hospital, Aurora, Colo.
authors: Clark
authors: C
authors: Lyda
authors: University of Colorado Hospital, Aurora, Colo; Department of Clinical Pharmacy, University of Colorado Skaggs School of Pharmacy and Pharmaceutical Sciences, Aurora, Colo.
authors: Douglas N
authors: DN
authors: Fish
authors: University of Colorado Hospital, Aurora, Colo.
authors: Gerard R
authors: GR
authors: Barber
authors: Department of Pharmaceutical Sciences, University of Colorado Skaggs School of Pharmacy and Pharmaceutical Sciences, Aurora, Colo.
authors: Michael F
authors: MF
authors: Wempe
authors: Division of Cardiothoracic Surgery, Department of Surgery, University of Colorado Anschutz Medical Center, Aurora, Colo.
authors: Joseph C
authors: JC
authors: Cleveland
mesh_terms: D000368:Aged; D000900:Anti-Bacterial Agents / Q000008:administration & dosage* / Q000097:blood / Q000493:pharmacokinetics; D019072:Antibiotic Prophylaxis; D001021:Aortic Valve / Q000601:surgery*; D001835:Body Weight; D002315:Cardiopulmonary Bypass; D003120:Colorado; D001026:Coronary Artery Bypass / Q000009:adverse effects; D004334:Drug Administration Schedule; D054796:Drug Dosage Calculations; D016903:Drug Monitoring; D005260:Female; D019918:Heart Valve Prosthesis Implantation / Q000009:adverse effects; D006801:Humans; D007263:Infusions, Parenteral; D008297:Male; D008875:Middle Aged; D013530:Surgical Wound Infection / Q000382:microbiology / Q000517:prevention & control*; D016896:Treatment Outcome; D014640:Vancomycin / Q000008:administration & dosage* / Q000097:blood / Q000493:pharmacokinetics
chemical_list: D000900:Anti-Bacterial Agents; D014640:Vancomycin