ABSTRACT

Major concern during cardiopulmonary bypass (CPB) is myocardial protection. The purpose of this study was to compare the effects of two techniques of terminating CPB on the biochemical markers of early myocardial injury.

Twenty-two adult patients with three or four vessel diseases undergoing elective coronary artery bypass grafting surgery were studied in a prospective randomized clinical design. All distal anastomoses were performed during a single period of cross clamping. Then, patients were randomized in terms of terminating CPB. In group 1 (n=10), CPB was terminated before the proximal anastomoses were completed and in group 2 (n=12), CPB was terminated after completion of all proximal anastomoses. Blood samples were collected from the coronary sinus as baseline (tl ), at the time of 0 (t2) and 5 minutes a{ter(t3) cross-clamp removal, 5 (14) and 15 minutes (t5) after CPB termination.

Plasma lactate, hypoxanthineand malondialdehyde (MDAJlevels significantly increased over time in both groups. MDA levels at t4 and t5 were higher and pH, base excess, ionized calcium and bicarbonate levels at t2 were significantly lower in group 2 when compared to group 1 (p< 0.05).

Two techniques of terminating CPB did not differ in terms of end­ products of energy metabolism and acid-base analysis as biochemical markers of myocardial status.