Brain injury is a serious problem after cardiac surgery. Brain injury can become evident in the form of stroke and cognitive dysfunction after surgery. The current neuromonitoring technique used is unable to monitor the region of the brain that is most susceptible to injury. This study aims to use a novel, non-invasive brain monitoring technique known as multichannel functional near infrared spectroscopy to assess brain oxygenation at multiple brain regions simultaneously during cardiac surgery. This research enables the investigators to understand the differences between regional brain oxygenation during cardiac surgery and to assess the feasibility and effectiveness of multichannel functional near infrared spectroscopy to be used as a future brain monitoring technique to detect brain injury in cardiac surgery.