Efficacy of Nalbuphine as an Adjuvant to Ropivacaine in Ultrasound-guided Supraclavicular Brachial Block A Prospective Randomized Controlled Study

Background: A brachial plexus block (BPB) provides anesthesia and analgesia with limited duration. Various opioids have been used as adjuvants of local anesthetics to improve the effects. Objective: The objective of this study was to evaluate the safety and effectiveness of nalbuphine used as an adjuvant to local anesthetic during the supraclavicular BPB. Materials and Methods: In this prospective, double-blinded, randomized controlled study, 90 American Society of Anesthesiology (ASA) Physical Status I and II patients (aged 20 to 65 y) of either sex undergoing upper limb orthopedic surgeries under ultrasound-guided supraclavicular BPB were randomly allocated into 3 groups: group C (n=30), group NL (n=30), and group NH (n=30) for analyses. Each patient received 18 mL of 100 mg ropivacaine solution combined with 2 mL of normal saline, 2 mL of 10 mg nalbuphine, or 2 mL of 20 mg nalbuphine. The time of onset and block duration of sensory block (SB) and motor block (MB), duration of analgesia, hemodynamic variables, and any adverse effects were assessed. Results: Compared with group C, the onset time of both SB and MB were significantly shortened. The SB and MB duration were significantly prolonged in group NL and group NH. There was no significant difference between the duration of analgesia in group NL and NH although the analgesia duration of both groups was longer than group C. But the incidence of side effects in group NH such as vomiting was significantly higher than group NL. Conclusions: Nalbuphine is an effective adjuvant to 0.5% ropivacaine in ultrasound-guided supraclavicular BPB. The dosage of 10 mg improves the quality of the anesthesia with less incidence of side effects.