Briefly, cerebral near-infrared spectroscopy (NIRS) or cerebral oximetry is a non-invasive monitor that estimates cerebral oxygenation through measurements of regional venous saturation. It is based on measuring intravascular oxyhemoglobin fraction in a small sample of cerebral cortex through the skull using near-infrared light spectroscopy. Cerebral oximetry examines all reflected light, from both pulsatile arterial and non-pulsatile venous blood, without requiring pulsatility, hence cerebral oximetry can continue to monitor brain oxygenation during both CPB and circulatory arrest. With this advantage, cerebral oximetry is widely utilized in our daily cardiac anesthesia practice, routinely for surgeries requiring circulatory arrest, and for other elective CABG and valve replacement/repair surgeries in some institutions. Despite its wide use, controversy still exists in its interpretation and ability to optimize cerebral outcome after cardiac surgery. Key questions to be answered are: 1) the desaturation threshold associated with poor prognosis; 2) the absolute desaturation value at which adverse clinical outcome increases, and 3); if the relative trend is more important to signal approaching deterioration. All of these questions are relevant to our clinical practice yet remain unanswered. Our research study aims to take a first step towards identification of the ideal method of utilizing cerebral oximetry in cardiac surgeries to improve neurological outcome through increasing precision in managing hemodynamic as well as laboratory values through a treatment algorithm.