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Changes in α-tocopherol and retinol levels during cardiopulmonary bypass correlate with maximal arterial partial pressure of oxygen

Cardiopulmonary bypass (CPB) is associated with oxidative stress. This study examined antioxidant levels in adults undergoing CPB surgery and their correlation with clinical variables. Arterial blood samples were obtained from 27 patients undergoing CPB. The time-course variation of vitamin C (spectrofluorimetry), α-tocopherol and retinol (HPLC) levels were determined. Plasma vitamin C rose initially but gradually decayed during reperfusion until 60% reduction of baseline values post-surgery. α-Tocopherol and retinol were reduced along CPB with post-operative values ∼25% lower than baseline. No significant changes were found for selenium and glutathione peroxidase. PaO2 values rose steadily throughout CPB. A correlation existed for α-tocopherol and retinol depletion vs maximal PaO2 throughout CPB but no correlation was found for antioxidant consumption vs duration of ischaemia and reperfusion and hypothermia level. In conclusion, consumption of arterial blood antioxidant vitamins occurs with CPB in relation with PaO2 levels but not for other clinical variables measured in this study.