Tramadol effects on perioperative shivering in lower limb orthopaedic surgeries under spinal anaesthesia.

Background: Shivering is one of the common complications of regional technique. Although shivering may have beneficial thermoregulatory effects, it places the patient under increased physiological stress.

Aims And Objectives: The study evaluated the efficacy of intravenous tramadol in the prevention and treatment of post-anaesthetic shivering following subarachnoid block for lower limb orthopaedic procedures.

Materials And Methods: This was a prospective, double-blind, randomized controlled trial conducted at the University of Benin Teaching Hospital, Benin City. In this study, ninety-five ASA physical status 1 or 2 eligible patients aged between 16 and 65 years were randomly allocated to either the tramadol group or the saline group. A randomization schedule with sealed envelopes was used. Each patient received 10mg diazepam the night before and morning of surgery. Spinal anaesthesia was induced in the sitting position with 15mg hyperbaric bupivacaine. The tramadol group received 0.5mg/kg IV made up to 2ml with saline while the control group was given 2 ml saline IV to ensure blinding.

Results: The incidence of shivering in the tramadol and the saline groups was 13.93% and 16.28% respectively. The overall incidence was 15%, (n=13). There was no statistical difference in the occurrence of shivering in both groups. However all patients who shivered during the surgical procedures, did not have a recurrence of shivering after a rescue dose of i.v tramadol 1mg/kg was administered.

Conclusion: Tramadol abolished shivering promptly when employed as a rescue medication with no recurrence. Also, tramadol reduces the severity of post-anaesthetic shivering.