mohammad reza hajiesmaeili department of anesthesiology and critical care medicine, iran university of medical sciences (iums), tehran, iran; pain research center, shahid sadoughi university of medical sciences and health services, yazd, iran mahsa motavaf rezvan medical research center, tehran, iran saeid safari department of anesthesiology and critical care medicine, iran university of medical sciences (iums), tehran, iran; department of anesthesiology and critical care medicine, iran university of medical sciences (iums), tehran, iran. tel: +98-9392117300, fax: +98-2166509059

M Dahlqvist R Venzin S König K Faber W Weinmann S Terbeck A Ceschi M W Dünser