Effect of Intravenous or Intrathecal Dexmedetomidine on Bupivacaine Spinal Block in Lower Abdominal Surgery

"Under a sterile technique, spinal anesthesia will be carried out using a 22-G Quincke spinal needle after skin infiltration with 2% lidocaine 3 ml a t the L3-L4 level, a midline approach in the sitting position, and then in the supine position.~Th e time of spinal injection will be considered time zero (T0). The I.V drug regimen will be started according to the group to which patients will be assigned.patients will receive intrathecal 15 mg hyperbaric bupivacaine together with 5 μg Dexmedetomidine in group 2"