 With over one million operations a year, cardiac surgery with cardiopulmonary bypass is one of the most common major surgical procedures worldwide 1. Acute kidney injury is a common and serious postoperative complication of cardiopulmonary bypass and may affect 25 to 50 of patients 2-4. Acute kidney injury carries significant costs 4 and is independently associated with increased morbidity and mortality 2,3. Even minimal increments in plasma creatinine are associated with an increase in mortality 5,6. 