The goal of this study is to determine whether or not exposure to blue spectrum light reduces acute kidney injury and systemic inflammation in subjects undergoing cardiopulmonary bypass. Subjects scheduled to undergo cardiopulmonary bypass surgery will be exposed to either bright (1000 lux) blue spectrum (480nm) light or to ambient, white fluorescent light for a 24 hour photoperiod the day prior to surgery and for a 24 hour photoperiod in the immediate postoperative period.