title: Vancomycin Dosing and Pharmacokinetics in Postoperative Pediatric Cardiothoracic Surgery Patients.
abstract: OBJECTIVE
  This study compared vancomycin trough concentrations and pharmacokinetic parameters in pediatric cardiothoracic surgery (CTS) patients versus those in controls receiving 20 mg/kg/dose, intravenously, every 8 hours.
  
  
  METHODS
  A retrospective study was conducted in children <18 years of age, following CTS, versus an age-and sex-matched control group. The primary objective was to determine differences in trough concentrations between groups. Secondary objectives included comparisons of pharmacokinetics between groups and development of vancomycin-associated acute kidney injury (AKI), defined as a doubling in serum creatinine from baseline. Also dosing projections were developed to target an area-under-the-curve-to-minimum inhibitory concentration (AUC:MIC) ratio of ≥400.
  
  
  RESULTS
  Twenty-seven patients in each group were evaluated. Mean trough concentrations were significantly different between groups (CTS: 18.4 mg/L; control: 8.8 mg/L; p < 0.01). Vancomycin-associated acute kidney injury AKI was significantly higher in the CTS group than in controls (25.9% versus 0%, respectively, p<0.01). There were significant differences in vancomycin elimination rates, with a high degree of variability, but no statistical differences in other parameters. Based on dosing projections, CTS patients would require 21 to 88 mg/kg/day, with a dosage interval determined by the child's glomerular filtration rate to achieve the target AUC:MIC ≥400.
  
  
  CONCLUSIONS
  Vancomycin dosage of 20 mg/kg/dose intravenously every 8 hours achieved significantly higher trough concentrations in CTS patients than in controls. Pharmacokinetic parameters were highly variable in CTS patients, indicating more individualization of dosage is needed. A future prospective study is needed to determine whether the revised dosage projections achieve the AUC:MIC target and to determine whether these regimens are associated with less vancomycin-associated AKI.
authors.affiliation: Primary Children's Hospital, Salt Lake City, Utah.
authors.forename: Emily C
authors.initials: EC
authors.lastname: Benefield
authors.affiliation: Department of Clinical Pharmacy, University of Tennessee Health Science Center College of Pharmacy, Nashville, Tennessee.
authors.forename: Tracy M
authors.initials: TM
authors.lastname: Hagemann
authors.affiliation: University of Oklahoma College of Medicine, Oklahoma City, Oklahoma.
authors.forename: H Christine
authors.initials: HC
authors.lastname: Allen
authors.affiliation: Department of Pharmacy: Clinical and Administrative Sciences, University of Oklahoma College of Pharmacy, Oklahoma City, Oklahoma.
authors.forename: Kevin
authors.initials: K
authors.lastname: Farmer
authors.affiliation: Department of Pharmacy: Clinical and Administrative Sciences, University of Oklahoma College of Pharmacy, Oklahoma City, Oklahoma.
authors.forename: Michael E
authors.initials: ME
authors.lastname: Burton
authors.affiliation: University of Oklahoma College of Medicine, Oklahoma City, Oklahoma.
authors.forename: Susana
authors.initials: S
authors.lastname: Chavez-Bueno
authors.affiliation: Department of Pharmacy: Clinical and Administrative Sciences, University of Oklahoma College of Pharmacy, Oklahoma City, Oklahoma.
authors.forename: Peter N
authors.initials: PN
authors.lastname: Johnson
keywords: cardiothoracic surgery; pediatrics; pharmacokinetics; vancomycin