Comparing Different Doses of Dexmedetomidine Combined with Ropivacaine for Ultrasound-Guided Supraclavicular Brachial Plexus Block in Upper Limb Surgeries - A Prospective Randomized Controlled Trial.

Background: Dexmedetomidine is used as an adjuvant to local anesthetic agents to provide prolonged analgesia in peripheral nerve blocks. This study aimed at determining the optimal dose of dexmedetomidine, which when combined with ropivacaine will produce a superior quality block in terms of extended pain-free period and reduced perioperative analgesic/opioid use, which in turn improves patient satisfaction.

Objective: The objective of the study is to assess the duration of analgesia with two different doses (25 μg and 50 μg) of dexmedetomidine with ropivacaine in supraclavicular brachial plexus block.

Subjects and methods: This prospective randomized controlled study included 50 patients undergoing upper limb surgeries under supraclavicular brachial plexus block randomly divided into two groups. Group D25 received 29 mL of 0.5% ropivacaine +25 μg dexmedetomidine diluted in 1 mL of normal saline (total 30 mL); Group D50 received 29 mL of 0.5% ropivacaine +50 μg dexmedetomidine diluted in 1 mL of normal saline (total 30 mL). Onset and duration of sensorimotor block, duration of analgesia, and time interval for the rescue analgesia and hemodynamic stability were observed.

Results: The mean onset of motor and sensory block was significantly higher in the D25 group (P = 0.001). The Visual Analog Scale pain scores and rescue analgesia consumption were significantly lower in the D50 group (P = 0.013, 0.001). The duration of analgesia was significantly higher in the D50 group (P = 0.001).

Conclusion: Dexmedetomidine 50 μg is an effective adjuvant dose to ropivacaine with insignificant hemodynamic changes with better duration of analgesia and lesser pain scores.