Cognitive Functions on Coronary Surgery

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.