Tramadol as adjunct to psoas compartment block with levobupivacaine 0.5%: a randomized double-blinded study.

BACKGROUND Tramadol has been administered peripherally to prolong analgesia after brachial plexus and neuraxial blocks. Our aim was to evaluate the systemic and perineural effects of tramadol as an analgesic adjunct to psoas compartment block (PCB) with levobupivacaine. METHODS In a randomized, prospective, double-blinded trial, 60 patients (ASA I-III), aged 49-88 yr, undergoing primary total hip or knee arthroplasty underwent PCB and subsequent bupivacaine spinal anaesthesia. Patients were randomized into three groups. Each patient received PCB with levobupivacaine 0.5%, 0.4 ml kg(-1). The control group (group L, n=21) received i.v. saline, the systemic tramadol group (group IT, n=19) received i.v. tramadol 1.5 mg kg(-1) and the perineural tramadol group (group T, n=20) received i.v. saline and PCB with tramadol 1.5 mg kg(-1). Postoperatively patients received regular paracetamol 6-hourly and diclofenac sodium 12-hourly. Time to first morphine analgesia, 24-hour morphine consumption, sensory block, pain and sedation scores and haemodynamic parameters were recorded. RESULTS Time (h) to first morphine analgesia was similar in the three groups [mean (SD)]: group L, 11.2 (6.6); group T, 14.5 (8.0); group IT, 14.6 (6.8); P=0.35. Twenty-four-hour cumulative morphine (mg) consumption was also similar in the three groups [group L, 21.9 (10.1); group T, 19.8 (6.7), group IT, 16.5 (9.5)], as were durations of sensory and motor block. There were no differences in the incidence of adverse effects except that patients in group IT were more sedated at 14 h than group L (P=0.02). CONCLUSION We conclude that our data do not support a clinically important local anaesthetic or peripheral analgesic effect of tramadol as adjunct to PCB with levobupivacaine 0.5%.