[1] Univ Penn, Dept Emergency Med, Robert Wood Johnson Fdn Clin Scholars, 1310 Blockley Hall,423 Guardian Dr, Philadelphia, PA 19104 USA
[2] Ben Taub Gen Hosp, Baylor Coll Med & Harris Hlth Syst, Sect Emergency Med, Emergency Ctr, Houston, TX 77030 USA
[3] Univ So Calif, Keck Sch Med, Dept Emergency Med, Los Angeles, CA 90033 USA
[4] Baylor Coll Med & Harris Hlth Syst, Michael E DeBakey Dept Surg, Houston, TX USA
[5] Michael E DeBakey VA Med Ctr, Houston Vet Affairs Ctr Innovat Qual Effectivenes, Houston, TX USA
[6] Baylor Coll Med, Houston, TX 77030 USA