[1] Wake Forest Univ, Dept Anesthesiol, 1 Med Ctr Blvd, Winston Salem, NC 27157 USA
[2] Univ Penn, Dept Emergency Med, Philadelphia, PA USA
[3] Univ Penn, Dept Med, Dept Med Ethics & Hlth Policy, Div Pulm Allergy & Crit Care, Philadelphia, PA USA
[4] Penn Med Ctr Addict Med & Policy, Philadelphia, PA USA