[1] Univ Michigan, Dept Surg, Ann Arbor, MI 48109 USA
[2] Univ Michigan, Dept Anesthesiol, Ann Arbor, MI 48109 USA
[3] VA NSQIP, Aurora, CO USA
[4] Washington Univ, Oklahoma Fdn Med Qual, St Louis, MO USA
[5] Washington Univ, Dept Surg, St Louis, MO USA
[6] Univ Washington, Dept Surg, Seattle, WA 98195 USA
[7] Univ Utah, Salt Lake City, UT USA
[8] Methodist Hosp, Houston, TX 77030 USA
[9] Harvard Univ, Brigham & Womens Hosp, Sch Med, Boston, MA 02115 USA
[10] Harvard Univ, Massachusetts Gen Hosp, Sch Med, Boston, MA USA
[11] Ohio State Univ, Columbus, OH 43210 USA
[12] Cleveland Clin Fdn, Cleveland, OH 44195 USA
[13] Univ Virginia, Charlottesville, VA USA
[14] Univ Maryland, Baltimore, MD 21201 USA
[15] Kaiser Sunnyside Med Ctr, Sunnyside, CA USA
[16] Amer Coll Surg, Chicago, IL USA