A Comparative Study of Isobaric Levobupivacainewith Fentanyl vs Isobaric Levobupivacaine with Dexmedetomidine in Lower Limb Orthopaedic Surgery Under Spinal Anaesthesia

INTERVENTION: Intervention1: Isobaric levobupivacaine 0.5 percentage with dexmedetomidine 5 mcg: Isobaric levobupivacaine 0.5 percentage combined with dexmedetomidine 5 mcg administered intrathecally as spinal anaesthesia for patients undergoing lower limb orthopaedic surgeries Control Intervention1: Isobaric levobupivacaine 0.5 percentage with fentanyl 25mcg: Isobaric levobupivacaine 0.5 percentage combined with fentanyl 25mcg administered intrathecally as spinal anaesthesia for patients undergoing lower limb orthopaedic surgeries CONDITION: Health Condition 1: M849‐ Disorder of continuity of bone, unspecified PRIMARY OUTCOME: Onset and duration of sensory and motor blockTimepoint: From the time of induction i.e after spinal anaesthesia until the patient regains sensory and motor activity SECONDARY OUTCOME: Hemodynamic changes intraoperative ; Time for first rescue analgesia ; Adverse effectTimepoint: After induction i.e.throughout the intraoperative period INCLUSION CRITERIA: Informed consent ASA physical status I II and III Patient posted for elective lower limb orthopaedic surgeries lasting less than 2 hours