| Description: |
Background Blood oxygen content and management during cardiopulmonary bypass (CPB), particularly during reperfusion phase after cross-clamping related ischemia, may influence systemic oxygen utilization, oxidative stress, and organ ischemia/reperfusion injury. These conditions may be highly relevant in patients undergoing coronary artery bypass grafting (CABG) due to coronary artery disease. The impact of a hyperoxia/normoxia strategy on metabolic efficiency, myocardial injury, and early clinical outcomes remains incompletely defined. Materials and methods We conducted a retrospective study including 50 patients undergoing isolated elective CABG with CPB. Patients were stratified into a normoxia (N) group (PaO 2 90–130 mmHg; n = 25) and a hyperoxia (H) group (PaO 2 >200 mmHg; n = 25). CPB trend parameters including PaO 2 , mixed venous oxygen saturation (SvO 2 ), indexed oxygen extraction ratio, and lactate levels were analyzed intraoperatively. Myocardial injury was assessed by serial troponin measurements. Early postoperative left ventricular ejection fraction (LVEF), need for inotropic support, ICU and hospital length of stay, as well as biomarkers of oxidative stress and hypoxia-related pathways, were evaluated. Exploratory outcomes included lactate kinetics (0, 6, 12, and 24 h), acute kidney injury (KDIGO criteria), new-onset atrial fibrillation within 48 h, duration of mechanical ventilation, and 30-days major adverse cardiac events (MACEs). Results Baseline, including preoperative LVEF, as well as operative characteristics, including types of grafts, modalities of revascularization (single vs jumpgraft) as well as cardiopulmonary bypass and aortic cross-clamp durations, were similar between groups. All grafts underwent flow assessment at the end of the operation to confirm the quality and appropriateness of perfusion. During CPB, indexed oxygen delivery was comparable; however, the hyperoxia group showed significantly higher arterial and mixed venous oxygen partial pressures, associated with a lower ... |