[1] Univ Hlth & Rehabil Sci, Qingdao Cent Hosp, Intens Care Med Dept, Qingdao 266000, Shandong, Peoples R China
[2] Univ Hlth & Rehabil Sci, Qingdao Cent Hosp, Dis Control Dept, Qingdao 266000, Shandong, Peoples R China
[3] Univ Hlth & Rehabil Sci, Qingdao Cent Hosp, Dept Gynaecol, Qingdao 266000, Shandong, Peoples R China
[4] Qingdao Women & Childrens Hosp, Childrens Hlth Dept, Qingdao 266000, Shandong, Peoples R China