Serum and tissue concentrations of intravenous cefotaxime during aortic surgery

Ten patients submitted to prosthetic aortic replacement received repeated intravenous bolus doses of cefotaxime (1 g) during induction of anaesthesia and at 2 hourly intervals during the operation. Hourly blood samples were taken and serum cefotaxime concentrations measured using high performance liquid chromatography. Subcutaneous fat, aortic and peripheral arterial wall samples were taken at various intervals intra-operatively, and tissue antibiotic levels were determined by bio-assay using an agar well diffusion method. Mean serum levels were consistently in excess of 50 mg/l which exceeds the MIC90 of virtually all aerobic and anaerobic pathogens. Tissue levels obtained exceeded the MIC90 of most pathogens. Cefotaxime would appear to provide adequate perioperative prophylactic cover in the dosage regimen used.