Background and Objectives: The majority of cardiac surgical procedures are performed using cardiopulmonary bypass and cardioplegia-induced cardiac arrest. Cardiac arrest and reperfusion may lead to ischemia-reperfusion injury of the myocardium. The aim of this study was to investigate whether gradual reperfusion with a slow increase in oxygen partial pressure leads to a reduction in reperfusion injury. Materials and Methods: Fifty patients undergoing elective cardiac surgery were included in this prospective randomized study. Patients in the hyperoxemic (control) group received conventional reoxygenation (paO₂ 250–300 mmHg). Patients in the normoxemic (study) group received gradual reoxygenation (1st-minute venous blood with paO₂ 30–40 mmHg, 2nd-minute arterial blood with paO₂ 100–150 mmHg). Periprocedural blood samples were taken serially, and markers of myocardial injury were analyzed. In addition, the influence of gradual reoxygenation on hemodynamics, inflammation, and the overall perioperative course was evaluated. Results: There was a trend toward higher CK levels in the hyperoxemia group without statistical significance; however, CK-MB and troponin T levels did not show any statistical difference between the two groups. Potassium concentrations in the coronary sinus were significantly higher in the hyperoxemia group at 3 and 8 min after opening of the aortic cross-clamp (6.88 ± 0.87 mmol/L vs. 6.30 ± 0.91 mmol/L and 5.87 ± 0.73 mmol/L vs. 5.43 ± 0.42 mmol/L, respectively; p = 0.03 and p = 0.02). All other measurements did not show a statistical difference between the two groups. Conclusions: The use of gradual reperfusion in cardiac surgery with cardiopulmonary bypass and cardiac arrest is safe. However, it does not reduce ischemia-reperfusion injury compared to standard hyperoxemic reperfusion.

The hemodynamic stabilization of patients after complex cardiac surgery is a daily challenge. The use of high doses of catecholamines is common but has potential adverse effects. Glibenclamide, a K_ATP blocker, seems to attenuate vasoplegia in different animal models of septic shock. Therefore, the aim of this study was to investigate the impact of Glibenclamide on the vasoplegic syndrome after cardiopulmonary bypass in a porcine model. In this experimental study, 20 landrace pigs were randomized into two groups and examined: In the control group, standard medical therapy, including norepinephrine, was used, and in the study group standard medical therapy plus additional Glibenclamide was administered. Following general anesthesia, prolonged cardiopulmonary bypass and aortic cross-clamping was performed. In the study group, Glibenclamide was administered 45 min after weaning from cardiopulmonary bypass. The dosage used was 10 mg/kg as a bolus, followed by a continuous infusion of 10 mg/kg/h. Hemodynamic and laboratory measurements were performed. Glibenclamide had a relevant effect on circulatory parameters. With increasing vascular resistance and blood pressure, norepinephrine was able to be reduced. While the heart rate dropped to physiological levels, the cardiac index decreased as well. The results lead to the conclusion that Glibenclamide was able to break through vasoplegic syndrome and could therefore serve as a potent drug to stabilize patients after cardiac surgery.