Administration of fentanyl before remifentanil-based anaesthesia has no influence on post-operative pain or analgesic consumption

Background: Remifentanil's short-acting analgesic effect and the potential of producing hyperalgesia is a challenge to post-operative pain control. This study investigated whether pre-treating the patients with fentanyl before remifentanil-based anaesthesia could reduce post-operative pain or analgesic consumption. Methods: One-hundred patients admitted for anterior cruciate ligament repair were included in a double-blind study. Propofol and remifentanil were used for general anaesthesia. Group Pre received fentanyl 1.5 mu g/kg intravenously (IV) and Group Post placebo before the remifentanil infusion. At the end of surgery, Group Pre received 1.5 mu g/kg and Group Post received 3.0 mu g/kg. Patient-controlled analgesia with fentanyl was used as analgesic rescue medication during the first 4 h post-operatively. Oxycodone 5 mg orally was taken as needed during the subsequent 4-24-h period. Results: A mean dose of remifentanil 0.43 mu g/kg/min was used for 90 min during surgery in both groups. There were no differences in the verbal rate scale (VRS) score or need of rescue analgesic medication between the groups during the first 4 h. Group Post had significantly less pain in the 4-24-h period after surgery, with a median VRS score of 'slight pain' vs. 'moderate pain' in Group Pre (P < 0.05). The oxycodone consumption was similar in both groups. Conclusion: Pre-treatment with fentanyl 1.5 mu g/kg IV yielded no reduction in post-operative pain or analgesic consumption after 90 min of remifentanil-based anaesthesia with 0.43 mu g/kg/min of remifentanil.