Continuous Epidural Infusion of Bupivacaine with Tramadol for Post-Cesarean Analgesia

Background: Tramadol administered epidurally is known to have one-thirtieth the potency of morphine for treatment of pain following abdominal surgery. We designed a prospective, randomized, controlled study to evaluate the analgesic efficacy and safety of combined epidural infusion of bupivacaine and tramadol with 2-day infusor as ompared to bupivacaine and morphine combined epidural infusion. Methods: Sixty healthy women scheduled for Cesarean delivery were assigned randomly in double- blind fashion: Group 1 (n=20) were given a mixture of morphine 10 mg(1 ml), 0.5% bupivacaine 40 ml and normal saline(NS) 40 ml; Group 2(n=20) a mixture of tramadol 300 mg(6 ml), 0.5% bupivacaine 40 ml and NS 54 ml; Group 3(n=20) or a mixture of tramadol 500 mg(10 ml), 0.5% bupivacaine 50 ml and NS 50 ml, of continuous dose via epidural route following 1% lidocaine 6 ml as bolus dose for 48 hours postoperatively. We evaluated the analgesic efficacy and side effects of these three groups using visual analogue pain scale (VAPS) and verbal rating scale (VRS). Results: VAPS of group 1 and 3 were lower than group 2, and VAPS of group 1 was lower than group 3(12, 24, 36, 48 hours). VRS of group 1 and 3 were lower than group 2 (12, 24, 36 hours). There were incidences of pruritus was 16 patients in group 1. Conclusions: Tramadol does possess the analgesia effect of morphine, but has the added analgesia following increment. Further research to determine the most effective administration method and reguired dosage of tramadol is further needed.