The Efficacy of Post-Cardiopulmonary Bypass Dosing of Vancomycin in Cardiac Surgery

Abstract

Objective. Vancomycin is administered widely to patients undergoing cardiac surgery as prophylaxis against resistant Gram-positive sternal wound and venous donor site infections. The purpose of this study was to determine the efficacy of a standardized prebypass and postbypass dosing regimen of vancomycin by assessing plasma concentrations in the immediate postoperative period and postoperative surgical site infections (SSIs). Design. Retrospective cohort study. Setting . Cardiothoracic surgical intensive care unit in a tertiary care academic medical center. Methods. A total of 34 consecutive adult patients who had undergone cardiac surgery with cardiopulmonary bypass (CPB) were analyzed retrospectively. Each patient received 1000 mg of vancomycin administered over 1 hour around the time of induction of anesthesia and 500 mg after discontinuation of CPB. Trough vancomycin levels were sampled in the intensive care unit 12 hours after the last dose given in the operating room. Along with patient characteristics, postoperative readmission rates and SSIs were recorded for 1 year after surgery. Results. The nadir serum vancomycin level before the next dose was 9.3 ± 4.5 µg/mL (mean ± standard deviation). One superficial SSI was noted. Readmission rate for SSIs was 2.94%. Conclusion . Vancomycin concentrations in the serum were greater than the minimum inhibitory concentration for most staphylococci ranging from 4 to 19.3 µg/mL producing acceptable therapeutic serum concentrations and low rate of infectious complications. Thus postbypass dosing is acceptable in vancomycin cardiac surgical prophylaxis.

Are children undergoing cardiac surgery receiving antibiotics at subtherapeutic levels?

“…We then searched reference lists for additional relevant articles. On a meta-analysis of studies describing cefuroxime pharmacokinetics and pharmacodynamics in pediatric patients, eight papers were reviewed to identify pharmacokinetic parameters [9–16] and the mean or median of reported values are listed in Table 1. While a 2-compartment model would give a more accurate representation of cefuroxime plasma concentration-time curves, reliable and reproducible PK parameters for a 2-compartment model have not been published.…”

“…Antibiotic levels may vary with age and weights given the variation in proportion of priming volume to circulating volume in different sized subjects. Given this risk, some investigators have advocated the administration of an additional dose of antibiotics with the priming volume [9, 10]. While cefuroxime, in particular, is a safe medication with minimal risk associated with supratherapeutic levels, further evidence is needed to justify adoption of a wide-spread change in published guidelines.…”