[1] Johns Hopkins Univ, Dept Anesthesiol & Crit Care Med, Baltimore, MD 21218 USA
[2] Zanvyl Krieger Sch Arts & Sci, Baltimore, MD USA
[3] Johns Hopkins Univ, Sch Med, Baltimore, MD USA
[4] Xi An Jiao Tong Univ, Affiliated Hosp 1, Dept Anesthesiol, Sch Med, Xian, Shaanxi, Peoples R China
[5] Isfahan Univ Med Sci, Sch Med, Esfahan, Iran
[6] Shiraz Univ Med Sci, Sch Med, Shiraz, Iran
[7] Burke Neurol Inst, White Plains, NY USA