Effect of the use of dexmedetomidine as an adjuvant in peribulbar anesthesia in patients presented for vitreoretinal surgeries

Background: Dexmedetomidine, if used in combination with a local anesthetic mixture in peribulbar anesthesia, may alter the block characteristic. This research aimed to study the influence of adding dexmedetomidine to local anesthetics in the peribulbar block. Methods: Sixty adult patients of both gender presented for vitreoretinal surgeries were enrolled in this prospective double-blinded study. They were randomly distributed into two equal groups. All the patients received peribulbar anesthesia with 10 ml mixture composed of 4 ml of plain bupivacaine 0.5%, 4 ml of lidocaine 2 % containing 50 IU hyaluronidase, and either 2 ml of normal saline (Control group) or 20 μg dexmedetomidine in (Dexmedetomidine group). The onset, the duration, and quality of sensory and motor blockade and the perioperative sedation were recorded. Results: As compared to the control group, dexmedetomidine when added to a local anesthetics in peribulbar block, significantly decreased the onset of anesthesia to 2.40 ± 1.50 min, fastened the onset of the lid akinesia to 2.93 ± 2.07 min and globe akinesia to 2.87 ± 1.96 min, increased the duration of lid akinesia to 137.00 ± 17.94 min and globe akinesia to 166.50 ± 21.34 min, and increased the time of the first request for postoperative analgesia to 185.83 ± 30.80 min (P