In most cardiovascular surgeries, patients are frequently followed up at hyperoxemic level for safety purposes against the risk of tissue hypoxia that may develop during surgery due to CPB use. At the level of hyperoxemia, there are opinions that the ischemia-reperfusion damage increases with the follow-up of CABG surgery, microcirculation is impaired and tissue oxygenation is impaired due to the resulting hyperoxemic vasoconstriction. Recent research has focused on evaluating optimal oxygen levels in CPB during cardiac surgery. However, the potential of tightly regulated intraoperative normoxia to improve POCD following cardiac surgery has not been studied prospectively.~The purpose of this study is to determine whether patients who underwent CPB and CABG, which were preserved under normoxic conditions during the intraoperative period, would have a lower incidence of early and late POCD than those exposed to hyperoxia.
The aim of this study is to examine the effects of different but safe levels of arterial oxygen levels used in cardiac surgeries on cerebral oxygenation during the operation. It is also to investigate the effect on cognitive functions in the postoperative period. For our study the investigators will conduct a randomized control trial. Patients will be randomly assigned to one of two possible study groups according to the arterial oxygen levels.If there is any abnormality in cerebral oxygen levels during surgery, necessary intervention will be made by doctors.