[Mediastinitis after cardiac surgery. A 10-year evaluation (1985-1995)]

From June 1985 to May 1995, 9,814 patients were operated for a cardiac procedure with cardiopulmonary by-pass. Mean age was 61,3 years. The most frequent procedure was coronary surgery (45%), followed by valvular surgery (34%) then combined surgery (11%) and other surgery (4%). 66 cases of mediastinitis were observed: 38 from June 1985 to May 1990 (first group), 28 from June 1990 to May 1995 (second group). The changes between the two groups was antibiotic prophylaxis using Cefuroxime in the first group and Cefamandole in the second and also an impairment of general status of the patients in the second group. Staphylococcus remains the most frequent organism in both groups and for Gram negative bacteria was less frequent in the second group. Several risks factors mediastinitis were identified (males, emergency, diabetes mellitus, obesity, redo, patient of first group, duration of Cardiopulmonary by pass for 100 minutes, mechanical ventilation greater than 48 hours) and the most important factor was the need for mechanical ventilation for more than 48 hours. The mortality rate was 39.4% (26 patients). Identified risk factors of mortality were age over 65 years, females, poor constitution, and cardio/thoracic ratio > 0.55.

Mediastinitis after cardiac surgery remains a serious complication. In this series we observed a decrease of mediastinitis rates, especially in the second group (p < 0.001). In high risk patients, specific preoperative methods of patient care may be able to prevent such complications. When mediastinitis appears, and when debridement is necessary, a cover procedure seems necessary in elderly or poor constitution patients.