Pre-emptive analgesia with tramadol: A comparative study between intramuscular, intravenous and epidural routes

Background: The effect of tramadol given by 3 different routes (i.m., i.v. and epidural) before skin incision on haemodynamics, stress response and postoperative pain was compared. Methods: Ninety patients undergoing lower abdominal surgery were divided randomly into three equal groups to receive tramadol 1.5 mg/kg i.m. (GI), i.v. (GII), and epidurally (GIII), 30 min, 5 min and 30 min, respectively, before induction of anaesthesia. A standardized anaesthetic technique was used, consisting of propofol, atracurium, and isoflurane in O2/N2O. No narcotic analgesic was given. Blood samples were drawn for assessment of cortisol, thyroxine and glucose at baseline, 30 min after skin incision and postoperatively. Mean arterial pressure (MAP) and heart rate (HR) were recorded every 30 min intraoperatively. MAP, HR and visual analogue score (VAS) were recorded every 30 min in the first two hours postoperatively then every 4 hours till 14 hours postoperatively. Time to 1st request of postoperative analgesia (TRA) was recorded as well. Results: Intraoperatively, no significant change from baseline in MAP or HR was observed in GI, while in GII and GIII, a significant reduction was observed (P < 0.05). Postoperatively, MAP was generally lower in GII and GIII than GI (P < 0.05). HR was lower (P < 0.05) in GII till 1 h and in GIII till 10 h than GI. TRA was longer (P < 0.05) in GII than GI and more so in GIII. VAS was lower in GII than GI and in GIII than the other two groups. Cortisol, thyroxine and glucose levels increased in all groups intraoperatively and postoperatively, with the highest rise in GI and the lowest in GIII. Conclusion: Pre-emptive epidural tramadol 1.5 mg,/kg results in more control of intraoperative and postoperative haemodynamics, more favourable postoperative analgesia and less stress response compared to the i.m. and the i.v. routes.