Background: Surgical-site infection is a common postoperative nosocomial infection. Surgeons frequently treat operative patients with protective antibiotics and often choose cefazolin as the drug. Treatment schemes include both preoperative intravenous dosing and intraoperative dosing by irrigation. This study was designed to measure cefazolin concentrations both in serum and in wound drain fluid after intravenous dosing and after irrigation.
Methods: The authors conducted an institutional review board-approved study involving randomized allocation of breast reduction patients to group 1 (preoperative intravenous dosing) or group 2 (intraoperative dosing by irrigation). Each patient had serum and wound drainage specimens measured over time for cefazolin concentrations. Cefazolin dosing was based on preparations commonly used in the authors' hospital. Results from 24 patients are reported.
Results: Patients treated by conventional preoperative intravenous dosing displayed the expected serum degradation curve. These patients also demonstrated wound drainage concentrations (peak, 22.49 microg/ml) for approximately 4 to 5 hours. Measured concentrations were above the minimum therapeutic concentration (8 microg/ml) for Staphylococcus aureus. Patients treated by wound irrigation also demonstrated serum concentrations above minimum therapeutic concentration. In addition, these patients' wound drain fluid demonstrated very high cefazolin concentrations (peak, 4185.93 microg/ml), which remained high for 24 hours.
Conclusions: Protective cefazolin concentrations in the wound can be achieved by both intravenous and irrigation delivery. Wound irrigation produces higher concentrations for longer periods of time.