[1] Stanford Univ, Dept Emergency Med, Stanford, CA 94305 USA
[2] Univ Penn, Leonard Davis Inst Hlth Econ, Philadelphia, PA 19104 USA
[3] New York Presbyterian Weill Cornell Med Ctr, New York, NY USA
[4] Univ Penn, Ctr Publ Hlth Initiat, Philadelphia, PA 19104 USA
[5] Univ Penn, Penn Nursing Sci, Philadelphia, PA 19104 USA
[6] Univ Penn, Perelman Sch Med, Div Traumatol Surg Crit Care & Emergency Surg, Philadelphia, PA 19104 USA
[7] Univ Penn, Perelman Sch Med, Ctr Clin Epidemiol & Biostat, Philadelphia, PA 19104 USA
[8] Univ Penn, Penn Injury Sci Ctr, Philadelphia, PA 19104 USA
[9] Thomas Jefferson Univ, Sidney Kimmel Med Coll, Dept Emergency Med, Philadelphia, PA 19107 USA
[10] Univ Penn, Perelman Sch Med, Dept Emergency Med, Philadelphia, PA USA