[1] Georgetown Univ, Sch Med, MedStar Georgetown Univ Hosp, Med, Washington, DC 20007 USA
[2] Harvard Med Sch, Beth Israel Deaconess Med Ctr, Dept Anesthesia Crit Care & Pain Med, Boston, MA 02115 USA
[3] Univ Arizona, Dept Anesthesiol, Coll Med, Phoenix, AZ USA
[4] Louisiana State Univ, Anesthesiol, Hlth Sci Ctr, Shreveport, LA 71105 USA