Background and objective: Local anaesthetics administered intraabdominally have been found to reduce analgesic requirements postoperatively after hysterectomy. This study was designed to assess the optimal dose of local anaesthetics for best pain relief.
Methods: Sixty patients undergoing abdominal hysterectomy were randomly divided into three groups to receive 10 ml h infusion of levobupivacaine intraabdominally postoperatively for 48 h in a double-blind manner: group L, 7.5 mg h; group M, 12.5 mg h and group H, 17.5 mg h. Pain intensity was measured using the numeric rating scale, ketobemidone consumption over 48 h was measured with a patient-controlled analgesia pump, recovery parameters, expiratory muscle strength, time to home readiness, plasma concentration of levobupivacaine and health-related quality of life were all measured at defined time points postoperatively.
Results: No differences were found between the active groups in pain intensity, recovery parameters or health-related quality of life. Pain intensity was maximal during 0-4 h and during coughing. Expiratory muscle strength decreased significantly during 0-4 h in all active groups, with no differences between the groups. Plasma concentration of levobupivacaine was below known toxic concentrations in humans, and no patient had symptoms of local anaesthetic toxicity. Health-related quality of life showed improved scores at 3 months after the operation compared with preoperative values, but no differences between the groups were found in any of the parameters.
Conclusion: Satisfactory analgesia can be achieved with low doses of levobupivacaine administered intraabdominally, except during the early postoperative period. No advantages were seen in this study when higher doses of levobupivacaine were administered as a continuous infusion for postoperative pain relief.