Cefamandole prophylaxis for cardiovascular surgery: a dosage comparison

For more than a decade, studies have indicated that antibiotic dosing immediately before and for a short time after surgery is effective in reducing the incidence of infectious complications of open-heart operations. At our institution we have used cefamandole, because of its broad spectrum of activity against bacteria common to the skin and respiratory system and its low toxicity. However, in response to more recent studies that threw doubt on the ability of the recommended dosing regimen (1.0 g given intravenously every six hours for three days) to maintain adequate intraoperative levels of cefamandole in heart tissue, we undertook an evaluation of a dosage of 2.0 g given intravenously every 6 hours for two days. This was a randomized study of 211 successive, evaluable, open-heart surgery patients who had no concurrent infections or cephalosporin allergy. Postoperatively, there were eight surgery-related infections (3.9%) and eight nosocomial infections in the 2.0-g dose group, compared with seven surgery-related infections (3.5%) and seven nosocomial infections in the 1.0-g dose group. These differences were not statistically significant. Tissue levels and cardiopulmonary bypass pump time were not risk factors for infection. We conclude that the 2.0-g doses over two days are no more effective than the 1.0-g doses over three days. However, when administration fees are considered, in a cost comparison, the 2.0-g dosing regimen is more economical than the 1.0-g regimen.