1 Department of Anesthesiology, Heping Hospital affiliated to Changzhi Medical College, No. 110 South Yanan Road, Changzhi, Shanxi 046000, China. Electronic address: lichunyuhpyy@yahoo.com.
2 Department of basic medicine, Changzhi Medical College, No.161 Jiefang East Street, Changzhi, Shanxi 046000, China.
3 Department of Anesthesiology, Heping Hospital affiliated to Changzhi Medical College, No. 110 South Yanan Road, Changzhi, Shanxi 046000, China.
4 Department of Neurology, Changzhi Second People's Hospital, No.83 Heping West Street, Changzhi, Shanxi 046000, China.
5 Department of Anesthesiology, Heping Hospital affiliated to Changzhi Medical College, No. 110 South Yanan Road, Changzhi, Shanxi 046000, China. Electronic address: jintai.jia@yahoo.com.