title: Tramadol added to 1.5% mepivacaine for axillary brachial plexus block improves postoperative analgesia dose-dependently.
abstract: Adjuncts to local anesthetics for peripheral plexus blockade may enhance the quality and duration of anesthesia and postoperative analgesia. The analgesic, tramadol, has a unique mechanism of action that suggests efficacy as such an adjunct. It displays a central analgesic and peripheral local anesthetic effect. We designed a prospective, randomized, controlled and double-blind clinical trial to assess the effect of tramadol added to brachial plexus anesthesia. One-hundred patients scheduled for carpal tunnel release surgery under brachial plexus anesthesia were randomized into four groups. All patients received 1.5% mepivacaine 40 mL plus a study solution containing either isotonic sodium chloride (Group P, n = 17), tramadol 40 mg (Group T(40), n = 22), tramadol 100 mg (Group T(100), n = 20) or tramadol 200 mg (Group T(200), n = 20). We evaluated the time of onset of anesthesia, duration of sensory and motor blockade, duration and quality of postoperative analgesia, and occurrence of adverse effects. Onset and duration of sensory and motor blocks were not different among groups. The number of patients requesting analgesia in the postoperative period was significantly less in the 3 tramadol groups compared with the placebo group (P = 0.02); this was also noted with the placebo and T(40) groups compared with the T(200) group. No statistical significance was demonstrated between the placebo and the T(40) group or the T(100) group and the T(200) group. Furthermore, there was a significant trend effect among groups applying the Cochran-Armitage tendency test (P = 0.003), suggesting a dose-dependent decrease for additional postoperative analgesia requirements when tramadol was added. Side effects did not differ among groups, although they were more frequently recorded in the T groups. Our study suggests that tramadol added to 1.5% mepivacaine for brachial plexus block enhances in a dose-dependent manner the duration of analgesia with acceptable side effects. However, the safety of tramadol has to be investigated before allowing its use in clinical practice.
  
  
  CONCLUSIONS
  Tramadol's unique mechanism of action suggests efficacy as a local anesthetic adjunct for peripheral plexus blockade. Our study demonstrates that tramadol, added to mepivacaine for brachial plexus anesthesia, extends the duration and improves the quality of postoperative analgesia in a dose dependent fashion with acceptable side effects.
authors.affiliation: *Department of Anesthesiology and Critical Care Medicine, Hôpital Central, Nancy Cedex, the †Department of Anesthesiology and Pain Management, Hôpital Caremeau, Nimes Cedex 9, France, the ‡Department of Plastic and Hand Surgery, Hôpital Jeanne d'Arc, Nancy, France, and the §Department of Clinical Epidemiology and Evaluation, Hôpital Marin, Nancy Cedex, France.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Robaux
authors.forename: Cornelia
authors.initials: C
authors.lastname: Blunt
authors.forename: Eric
authors.initials: E
authors.lastname: Viel
authors.forename: Philippe
authors.initials: P
authors.lastname: Cuvillon
authors.forename: Philippe
authors.initials: P
authors.lastname: Nouguier
authors.forename: Gilles
authors.initials: G
authors.lastname: Dautel
authors.forename: Sylvie
authors.initials: S
authors.lastname: Boileau
authors.forename: Florence
authors.initials: F
authors.lastname: Girard
authors.forename: Hervé
authors.initials: H
authors.lastname: Bouaziz
mesh_terms: D000328:Adult; D000368:Aged; D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000009:adverse effects; D000779:Anesthetics, Local; D001917:Brachial Plexus; D002349:Carpal Tunnel Syndrome / Q000601:surgery; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D008619:Mepivacaine; D008875:Middle Aged; D009407:Nerve Block; D019637:Orthopedic Procedures; D010147:Pain Measurement; D010149:Postoperative Pain / Q000517:prevention & control*; D020250:Postoperative Nausea and Vomiting / Q000453:epidemiology; D011446:Prospective Studies; D014147:Tramadol / Q000008:administration & dosage / Q000009:adverse effects
chemical_list: D000701:Analgesics, Opioid; D000779:Anesthetics, Local; D014147:Tramadol; D008619:Mepivacaine