Kidney injury is a serious complication of cardiac surgery that occurs in up to 30% of patients and increases the risk of adverse outcomes. Kidney injury initiates when oxygen supply to the kidney drops below levels that are needed for normal cellular function, causing tissue oxygen deficiency (hypoxia), activation of the inflammatory cascade, and oxidative stress. Together, these events further impair tissue oxygenation, culminating in impaired kidney function due to cellular injury and death.