PROPHYLACTIC ANTIBIOTICS IN CARDIAC-SURGE RY

Cardiac surgery enters mainly into the class I of Altemeier (''clean s urgery''). However, many factors may explain an intraoperative contami nation: surgery of long duration, extra-corporeal circulation, aspirat ion of blood and air, immunodepression...). In fact, the infectious ri sk decreases from about 25 % with placebo to 5 % with prophylactic ant ibiotics. The staphylococcal infections are the most frequent (mediast initis, endocarditis, parietal infections...). Cephalosporins, particu larly of second-generation type (cefamandole, cefuroxime), perform bet ter than antistaphylococcal penicillins. The combination with an amino side may be used when Gram negative bacilli infection prevalence is hi gh. Vancomycin is efficient but hypotension and renal impairment have been reported. Therefore, vancomycin is used in patients allergic to c ephalosphorins, when a high prevalence of methicillin-resistant Staphy lococcus or enterococci infections is reported, or when the patient ha s recently received broad-spectrum antimicrobial therapy. The antibiot ic doses must take into account the haemodilution due to extracorporea l circulation and the necessity to obtain sufficient serum concentrati ons throughout surgery. A prophylaxis of more than 48 hours is not ass ociated with an improved outcome. In cardiac transplantation a prophyl axis is essential, but is still questionned during the insertion of pa ce-markers. In any case, the antibiotic prophylaxis must take into acc ount the bacterial prevalence of each institution.