Duke University Hospital has had a Pre-Operative Screening Unit (POSU) in place for the past 16 years to optimize patients prior to surgery, but until recently, there were no hard data on surgical cancellation rates. Now, a retrospective analysis has revealed that fewer cancellations occur when patients are seen in the POSU. During the study period (June 1, 2011 to May 31, 2012), Duke had 37 ORs on the main campus and 9 at its free-standing ambulatory surgery center (ASC). The study looked at the surgical schedules 24 hours prior to surgery up until surgical start time. Any cancellation within this time period was counted in the study.