Serum antibiotic concentrations pre- and postcardiopulmonary bypass.

Serum concentrations of cephalothin or kanamycin, or both, were determined in 53 patients undergoing cardiopulmonary bypass. Conventional doses of these antibiotics did not provide serum levels above the accepted minimum inhibitory concentrations in children. Adults had adequate serum antibiotic concentrations only when the antimicrobials were administered within 4 h of beginning cardiopulmonary bypass. The impact of these variations upon the occurrence of infectious endocarditis could not be appraised since no cases of infective endocarditis were seen during a 4-month postoperative period.