RT Journal Article SR Electronic T1 Preoperative Epidural Tramadol, a Mixed Opioid and Monoaminergic Agonist for Perioperative Analgesia and Antinociception JF Regional Anesthesia: The Journal of Neural Blockade in Obstetrics, Surgery, & Pain Control JO Reg Anesth Pain Med FD BMJ Publishing Group Ltd SP 9 OP 9 DO 10.1136/rapm-00115550-199318041-00010 VO 18 IS Suppl 4 A1 P Naji A1 M Farschtschian A1 OHG Wilder-Smith A1 CH Wilder-Smith YR 1993 UL http://rapm.bmj.com/content/18/Suppl_4/9.abstract AB