Aminoglycoside toxicity following antibiotic prophylaxis in cardiac surgery

We have reviewed experience with aminoglycosides in cardiac surgical prophylaxis from 1984 to 1989. In the first two years, prospectively randomized trials (517 patients) allowed comparison of tobramycin (three-day course) with a non-toxic antibiotic, teicoplanin. A significant excess rise in serum creatinine was present at the end of the first postoperative week in patients given tobramycin (165 vs 149 patients, 95% CI 3-17 microM. P less than 0.01, which was most marked in ten oliguric patients with trough serum levels over 2 mg/l (95% CI 7-52 microM). However, no patient needed haemodialysis and only one case of possible ototoxicity was identified. During the next three years, of 912 patients given two to three days gentamicin, 29 patients were shown to have potentially toxic serum levels and oliguria. Three individual cases are described, including one of ototoxicity and one of nephrotoxicity neeeding haemodialysis. The hazards of aminoglycoside toxicity are probably small compared with the failure of other antibiotics to cover staphylococci that may later cause wound infection or endocarditis. However, surgeons should probably be advised to check the aminoglycoside level in all patients on the first post-operative day.