Role of Dexmedetomidine as Synergistic Agent

Evaluate the efficacy of Dexmedetomidine when used adjunctively with hyperbaric bupivacaine in extending the duration of sensory and motor blockade in subarachnoid anesthesia.

Sensory Blockade Duration: This refers to the time interval from the administration of the subarachnoid block until the complete recovery of sensory function in the dermatomes affected by the anesthesia. It will be assessed using standardized sensory tests, such as pinprick or cold sensation, within the affected dermatomes. Motor Blockade Duration:It encompasses the time from the onset of motor blockade to the complete recovery of motor function and will assessed by evaluating muscle strength and movement capability using modified Bromage score as 0=Subject is able to lift the leg straight and move the hip, knee and ankle. 1. Subject is unable to lift the leg straight but is able to lift the leg straight but is able to flex the knee and ankle freely. 2. Subject is unable to flex the knee and hip, but is able to flex the ankle. 3. Subject is unable to flex the ankle, knee, and hip, but is able to move toes. 4. No movement in the lower extremity.

Investigate the safety profile of Dexmedetomidine in combination with hyperbaric bupivacaine, in term of adverse events such as hypotension, bradycardia, and patient satisfaction.

Sedation levels will be assessed using the Ramsay score 1. Awake; agitated or restless or both 2. Awake; cooperative, oriented, and tranquil 3. Awake but responds to commands only 4. Asleep; brisk response to light glabellar tap or loud auditory stimulus 5. Asleep; sluggish response to light glabellar tap or loud auditory stimulus 6. Asleep; no response to glabellar tap or loud auditory stimulus Adverse Event: will be measured in following term Hypotension: defined as a systolic blood pressure less than 90 mm Hg or a mean arterial pressure below 60 mm Hg. Bradycardia:defined as a heart rate of less than 50 beats per minute. Patient Satisfaction:defined in terms of subjective assessment of the patient's physical and emotional well-being during the procedure include observed signs of distress, facial expressions, and verbal feedback. Patients' satisfaction will be assessed using a 10cm Visual Analogue Score. Where 10cm denoted maximal satisfaction and 0cm denoted minimal.