The blind, randomized, prospective, clinical trial study was carried out on sixty patients, divided into two groups (30 patients/group): the first group received intrathecal sufentanil (5 mcg) added to 0.18 mg/kg of 0.5% hyperbaric bupivacaine and the second one received intrathecal sufentanil (7.5 mcg) added to 0.18 mg/kg of 0.5% hyperbaric bupivacaine for nephrolithotomy from October, 2010 to April, 2011 at the Department of Anesthesiology, 103 Hospital. Download Link: eBook có trong tuyển tập DVD Y Học http://hocvienquany.vn/Tapchi/Data/TapTin/2012_3_21hothanhtuan.pdfhttps://www.mediafire.com/?hntqghhkmizgiq