Penetration of penicillins into cardiac valves and auricles of patients undergoing open-heart surgery

Evaluation of cloxacillin concentrations in plasma and muscle tissue during cardiopulmonary bypass

Concentrations of cloxacillin in plasma and deep thoracic muscle tissue were measured in 10 patients who underwent elective coronary bypass surgery or valve replacement. One g of cloxacillin was administered after the induction of anaesthesia and 1 g cloxacillin was added to the oxygenator pump priming fluid before the start of the procedure. Blood and tissue samples were obtained before, during and after cardiopulmonary bypass. The relation between unbound plasma concentrations and total tissue contents of the drug was calculated. It was shown that measurement of the free plasma concentration may provide fairly reliable information on the free concentrations of cloxacillin in the tissues, and that determination of tissue contents may therefore not be necessary. Due to the administration of the second dose of cloxacillin at the start of cardiopulmonary bypass free tissue contents were just adequate in most patients. However, to obtain adequate tissue concentrations after bypass it is recommended that a third dose of the antibiotic be administered before the end of the operation.

Serum levels of cloxacillin and benzylpenicillin in adults undergoing open-heart surgery

Serum levels of cloxacillin and benzylpenicillin were monitored in 35 consecutive adult patients undergoing elective open-heart surgery. Serial serum samples were analyzed during a 24-hour period. After oral intake of cloxacillin and phenoxymethylpenicillin on the preceding evening, very low concentrations remained in serum at the start of operation. Such preoperative medication is inappropriate. Intravenously administered cloxacillin (2 g) and benzylpenicillin (3 g) appeared to be adequate during the first 4 hours of surgery, as the serum half-life of the drugs was twice as long in the patients as in healthy adults, but repetition of the doses is recommended for further antibiotic protection during surgery.

Comparative study between two prophylactic antibiotic regimens of cefamandole during coronary artery bypass surgery

In two groups of patients undergoing coronary artery bypass grafting (CABG), two different regimens of antibiotic prophylaxis with cefamandole nafate were compared. In Group 1, 30 mg per kilogram of body weight was administered intravenously during induction of anesthesia. In Group 2, a second dose of 15 mg/kg was administered intravenously shortly before cannulation. Serum and tissue levels in the right atrium, the pericardium, and the sternum were determined using high-pressure liquid chromatography. The results showed that in Group 2 the serum levels were significantly higher from 48 minutes onward after induction and remained at an acceptable level during CABG. The tissue levels in the sternum and pericardium were also significantly higher in Group 2 compared with Group 1. It is concluded that a second dose of cefamandole (15 mg/kg) shortly before the beginning of cardiopulmonary bypass is recommended, particularly for high-risk patients.