Influence of timing of antibiotic administration on tissue concentrations during surgery

Background Prophylactic antibiotics must be administered so as to achieve adequate tissue levels before the initial surgical incision. We characterized antimicrobial tissue concentrations following intravenous administration at various times prior to surgical incision. Patients and Methods Twelve patients scheduled for elective colorectal surgery were randomized to receive cefmetazole 2 g by intravenous push either immediately prior to incision or 15 to 60 minutes prior. Blood and woundmuscle samples were obtained at predetermined intervals and assayed by high-performance liquid chromatography. Results Tissue distribution of the study drug was extremely rapid. All patients had theoretically adequate tissue levels at the time of incision. Levels above MIC90 of the common pathogens were sustained throughout the surgical procedure regardless of the timing of administration. Conclusions Administration of cefmetazole immediately prior to surgical incision should be effective prophylaxis for surgical wound infections.