There is a need for monitoring of cerebral perfusion during cardiac surgery to reduce neurological complications. Cerebral perfusion is a major factor for regional and global imbalance in oxygen supply-demand, which may result in brain injury following cardiac surgery. Cerebral oximetry (near infrared spectroscopy) is a means to monitor regional cerebral perfusion. It was developed as a non-invasive technology, similar to pulse oximetry, for the continuous assessment of cerebral blood flow. Published studies have demonstrated that the use of cerebral oximetry reduces both postoperative cognitive impairment and the length of hospital stay.