Gentamycin serum levels in a patient with severe skin damage

Pseudomonas aeruginosa grew in blood cultures taken from a 30-year-old woman with a 45% burn of second and third degree. Because of wound infection, skin grafting was unsuccessful and the wounds were left uncovered and treated topically with Eusol and saline solution. During this period 7 mg/kg gentamycin was administered to the patient daily; the blood level of the antibiotic was 3 microgram/ml, rather than the expected 8--12 microgram/ml in a patient without burns. On the eighth day, 40% of the administered dose was recoverable in the urine. With partial covering of the wounds, a dose of 5 mg/kg gentamycin daily gave blood levels of 6.5 microgram/ml. When most of the burn wounds were covered, a dose of 5 mg/kg gentamycin daily gave a blood level of 12 microgram/ml. Kidney function remained normal throughout the whole period. The possibility that gentamycin was eliminated through the burn wounds is suggested.