Dexmedetomidine can extend the duration of analgesia of levobupivacaine in transversus abdominis plane block: a prospective randomized controlled trial

Background: Local analgesia technique has important advantages to manage postoperative pain; however, the duration of pain relief is relatively short due to the pharmacological characteristic of local anesthetics. Hence, in the current study, we planned to explore the hypothesis that adding dexmedetomidine to levobupivacaine in transversus abdominis plane (TAP) block prolongs the duration of analgesia. Methods: Sixty patients scheduled for elective abdominal hysterectomy were divided into two groups by a randomized and double-blinded method. Patients in the Control group (n = 30) received TAP block, using 40 mL of 0.25% levobupivacaine, and patients in the Dexmedetomidine group (Dex group) received the same volume and concentration of levobupivacaine but with additional 0.5 μg/kg of dexmedetomidine for TAP block. Time for initial requirement of postoperative analgesic, total requirement of sufentanil for postoperative analgesia, Visual Analogue Scale (VAS) at different endpoints, and side effects were recorded. Results: The duration of analgesia was significantly longer in the Dex group than in the Control group (905.0 ± 114.2 min vs. 741.4 ± 105.3 min, P < 0.001), and the consumption of the rescue sufentanil in the first 24 hours postoperatively was less in the Dex group than in the Control group (29.4 ± 1.2 μg vs. 47.4 ± 2.0 μg, P < 0.001). The VAS point at rest was significantly lower in the Dex group than in the Control group at 8 and 12 hours (P < 0.05). The patient satisfaction with postoperative analgesia in the Dex group was better than in the Control group (P = 0.006). Side effects in the two groups were similar (P > 0.05). Conclusions: The addition of dexmedetomidine to levobupivacaine in TAP block can prolong the duration of analgesia and reduce postoperative analgesic requirements without additional side effects.