A clinical study on cefuzonam concentrations in myocardium in open heart surgery

The distribution of cefuzonam (CZON) was studied in 20 adults undergoing open heart surgery. In groups I (n=ll) and II (n=9), CZON (2g) was intravenously infused at the time of induction of anesthesia; and in group II an additional 2g was administered at the time of commencement of extracorporeal circulation (ECC). Just prior to and following the ECC, samples of blood and right auricle were taken for examination. CZON concentrations in serum and myocardium were measured using the thin-layer cup method with Esherichia coli NIHJ as the test organism. CZON concentrations in myocardium prior to ECC were 48.9 µg/g and 39.0/µg/g for groups I and II, respectively. The ratios of intramyocardial to serum CZON concentration were 0.40 and 0.45 for groups I and II, respectively, revealing no significant difference between the 2 groups. Following ECC, intramyocardial CZON concentrations were 20.8 µg/g for group I and 33.2 µg/g for group II; while the ratios were 0.43 and 0.59 for groups I and II, respectively. Again, there were no significant differences. From the above findings it may be concluded that: 1. There was good distribution of CZON in myocardium, with a concentration well above MIC80. 2. Therapeutic concentrations of CZON were maintained in myocardium for 6 hours, suggesting that initial infusion of 2g CZON is sufficient for prophylaxis in routine open heart surgery.