The efficacy and safety of three concentrations of levobupivacaine administered as a continuous epidural infusion in patients undergoing orthopedic surgery

We evaluated the efficacy and safety of three concentrations of levobupivacaine infused epidurally as analgesia for patients undergoing orthopedic procedures. Patients undergoing elective hip or knee joint replacement were enrolled in the study (n = 105). Sensory blockade was established preoperatively with 10-15 mL of 0.75% levobupivacaine. Patients were then randomized to receive 0.0625%, 0.125%, or 0.25% levobupivacaine as a continuous epidural infusion at 6 mL/h for 24 h. IV morphine patient-controlled analgesia was given as rescue analgesia, and time to first request for analgesia and total dose of morphine consumed were recorded. Sensory blockade, motor blockade, visual analog scale pain score, and cardiovascular variables were also recorded at regular intervals postoperatively. Ninety-one patients were included in the primary intent-to-treat analysis. Total normalized dose of morphine, number of patient-controlled analgesia requests, and overall postoperative visual analog scale pain scores were significantly lower for the 0.25% group compared with the other two groups, and the time to first request for rescue analgesia was longer. There was no significant difference between the 0.125% and 0.25% groups in terms of maximum motor blockade achieved and time to minimal motor blockade. Safety data were equivalent among the three groups. We conclude that levobupivacaine as a continuous epidural infusion provided adequate postoperative analgesia and that the 0.25% concentration provided significantly longer analgesia than 0.125% or 0.0625% levobupivacaine without any significant increase in detectable motor blockade relative to the 0.125% group. Postoperative epidural infusion of levobupivacaine can provide safe and effective analgesia for patients having hip or knee joint replacement. Of the three concentrations we infused at a constant rate, 0.25% provided significantly better pain relief.