[1] Johns Hopkins Sch Med, Dept Anesthesiol & Crit Care Med, Baltimore, MD 21029 USA
[2] Johns Hopkins Sch Med, Dept Phys Med & Rehabil, Baltimore, MD 21029 USA
[3] Uniformed Serv Univ Hlth Sci, Dept Anesthesiol, Bethesda, MD 20814 USA
[4] Univ Hosp Cleveland, Dept Anesthesiol, Case Western Reserve Sch Med, Cleveland, OH 44106 USA
[5] Harvard Univ, Sch Med, Dept Anesthesia, Massachusetts Gen Hosp, Boston, MA 02115 USA
[6] Uniformed Serv Univ Hlth Sci, Dept Phys Med & Rehabil, Bethesda, MD 20814 USA
[7] Reg Med Ctr, Dept Surg, Pain Treatment Ctr, Landstuhl, Germany
[8] Case Western Reserve Univ, Dept Anesthesiol, Louis Stokes Cleveland VA Med Ctr, Cleveland, OH 44106 USA
[9] Weill Cornell Med Univ, Mem Sloan Kettering Canc Ctr, Dept Anesthesiol, New York, NY USA
[10] Walter Reed Natl Mil Med Ctr, Dept Surg, Anesthesia Serv, Bethesda, MD USA
[11] Dist Columbia VA Hosp, Dept Internal Med, Washington, DC USA
[12] Dist Columbia VA Hosp, Dept Neurol, Washington, DC USA
[13] San Antonio Mil Med Ctr, Dept Anesthesiol, Pain Treatment Ctr, San Antonio, TX USA
[14] Uniformed Serv Univ Hlth Sci, Dept Anesthesiol, Bethesda, MD 20814 USA
[15] Penn State Hershey Med Ctr, Dept Anesthesiol, Hershey, PA USA
[16] Penn State Hershey Med Ctr, Dept Neurol, Hershey, PA USA