[1] Sichuan Univ, West China Hosp, Dept Neurosurg, Chengdu 610041, Peoples R China
[2] Sichuan Univ, West China Univ Hosp 2, Inst Drug Clin Trial GCP, Chengdu 610041, Peoples R China
[3] Sichuan Univ, Dis Women & Children, Minist Educ, Chengdu 610041, Peoples R China
[4] Sichuan Univ, West China Hosp, Dept Crit Care Med, Chengdu 610041, Peoples R China