Antibiotic prophylaxis with cefazolin and gentamicin in cardiac surgery for children less than ten kilograms

Antibiotic prophylaxis is recommended in pediatric cardiac surgery, but no data concerning the current antibiotic regimen were available.

Prospective study from April to June 2000.

University hospital operating room and postoperative intensive care unit.

Nineteen consecutive infants less than 10 kg with normal renal function undergoing cardiac surgery with cardiopulmonary bypass longer than 30 minutes.

Intravenous administration of cefazolin, 40 mg/kg, and gentamicin, 5 mg/kg, at induction of anesthesia; followed by cefazolin, 35 mg/kg every 8 hours, and gentamicin, 2 mg/kg every 12 hours, over 48 hours.

Levels of serum antibiotics were measured: cefazolin (microbiologic) and gentamicin (fluorescence immunoassay) with 8 intraoperative and 5 postoperative samplings. Intraoperatively, cefazolin levels decreased from 166 +/- 44 (mean +/- standard deviation) down to 54 +/- 16 microg/mL and gentamicin from 20.8 +/- 9.5 down to 5.9 +/- 1.5 microg/mL. The postoperative trough levels were 12 +/- 7, 15 +/- 10, and 19 +/- 22 microg/mL for cefazolin and 1.1 +/- 0.5, 0.8 +/- 0.4, and 0.8 +/- 0.9 microg/mL for gentamicin.

Antibiotic serum levels are consistent with satisfactory efficacy, but intraoperative gentamicin peak levels appeared too high.