Tehran University of Medical Sciences Archives of Anesthesiology and Critical Care 2423-5849 0 0 2026 10 01 1617 1617 Ehsan Iravani Department of Anesthesiology and Critical Care, Sina Hospital, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran. Kousha Farhadi Anesthesia, Critical Care, and Pain Management Research Center, Tehran University of Medical Sciences, Tehran, Iran. Parisa Kianpour Anesthesia, Critical Care, and Pain Management Research Center, Tehran University of Medical Sciences, Tehran, Iran. Pejman Pourfakhr Anesthesia, Critical Care, and Pain Management Research Center, Tehran University of Medical Sciences, Tehran, Iran. Atabak Najafi Anesthesia, Critical Care, and Pain Management Research Center, Tehran University of Medical Sciences, Tehran, Iran. Reza Shariat Moharari Anesthesia, Critical Care, and Pain Management Research Center, Tehran University of Medical Sciences, Tehran, Iran. Farhad Etezadi Anesthesia, Critical Care, and Pain Management Research Center, Tehran University of Medical Sciences, Tehran, Iran. Reza Bahman Anesthesia, Critical Care, and Pain Management Research Center, Tehran University of Medical Sciences, Tehran, Iran. Hamidreza Sharifnia Anesthesia, Critical Care, and Pain Management Research Center, Tehran University of Medical Sciences, Tehran, Iran. Mohammad Reza Khajavi Anesthesia, Critical Care, and Pain Management Research Center, Tehran University of Medical Sciences, Tehran, Iran. Mohamadreza Neishaboury Anesthesia, Critical Care, and Pain Management Research Center, Tehran University of Medical Sciences, Tehran, Iran. 2026 04 20 2026 05 04 Background: Using lidocaine for intravenous regional anesthesia (IVRA) or the Bier block is a common technique for limb surgeries but is limited by short block duration and tourniquet pain. Dexmedetomidine has shown promise as an adjuvant to lidocaine for the Bier block. This study aims to assess the safety and efficacy of adding dexmedetomidine to lidocaine. Methods: In this randomized, double-blind, controlled trial, 32 candidates of upper-limb surgery were allocated to receive 3 mg/kg lidocaine 2% (group LS) alone or combined with 0.5 µg/kg dexmedetomidine (group LD), comparing the onset and duration of sensory and motor blocks between the two groups. Secondary outcomes included sedation levels, hemodynamic stability, and satisfaction scores of patients, surgeons, and anesthesiologists. Results: Patients in the LD group showed significantly lower sensory block onset time (38.8 ± 19.0 vs. 60.6 ± 14.8 seconds, P = 0.001) and longer sensory (55.8 ± 15.9 vs. 31.0 ± 8.5 minutes, P < 0.001) and motor block durations (47.2 ± 17.4 vs. 26.6 ± 8.7 minutes, P < 0.001). They also experienced deeper sedation (P = 0.028) and greater satisfaction with the procedure (P = 0.045). Although the LD group showed statistically lower heart rate and systolic blood pressure after tourniquet deflation compared to the LS group, the differences were clinically negligible. Conclusion: The addition of dexmedetomidine to lidocaine provides a faster onset of sensory block, prolongs sensory and motor blocks, and improves patient sedation and satisfaction with minimal clinical hemodynamic effects, enhancing efficacy while maintaining reasonable safety. https://aacc.tums.ac.ir/index.php/aacc/article/view/1617