H L Yang F C Liu S C Tsai P K Tsay H T Lin H E Liu

ali karbasfrushan department of anesthesiology, emam reza hospital, kermanshah university of medical sciences, kermanshah, iran. behzad hemmatpoor department of anesthesiology, emam reza hospital, kermanshah university of medical sciences, kermanshah, iran. behnam reza makhsosi departments of surgery, emam reza hospital, kermanshah university of medical sciences, kermanshah, iran. tayebeh mahvar m.sc degree in nursing (medical-surgical),taleghani hospital, kermanshah university of medical sciences, kermanshah, iran. parisa golfam department of anesthesiology, emam reza hospital, kermanshah university of medical sciences, kermanshah, iran. behrooz khiabani member of iranian epidemiologist association.