Evaluation of cefazolin antimicrobial prophylaxis during cardiac surgery with cardiopulmonary bypass

Objectives Although clinical practice guidelines recommend standard cefazolin antimicrobial prophylaxis (AP) dosing for cardiac surgery, limited data exist as to whether adequate concentrations are achieved in this patient population. The goal of our study was to characterize intraoperative cefazolin concentrations particularly at wound closure with regards to maintaining target cefazolin closure concentrations ≥40 mg/L. Methods Adults undergoing cardiac surgery with cardiopulmonary bypass (CPB) and receiving cefazolin AP according to protocol were studied. Blood samples were collected after the preoperative cefazolin dose, prior to intraoperative cefazolin doses and at wound closure. Intraoperative trough and closure concentrations were characterized and evaluated against a target threshold of ≥ 40 mg/L (≥8 mg/L unbound, assuming 80% protein binding). Results Fifty-five subjects (64.9 ± 10.4 years, 89.7 ± 16.5 kg, CLCR >50 mL/min/72 kg) completed the study. Total cefazolin concentrations were