Primary Outcome Variables:

We will assess postoperative cognitive function and quality of recovery utilizing

1.    1.  Mini- Mental State Examination (MMSE) Scores.

2.     2.  15-item quality of recovery score (QoR15) questionnaire.

 Secondary Outcome Variables:

1.     Intraoperative propofol consumption.

2.     Intraoperative and postoperative fentanyl requirement.

3.     Haemodynamic changes.

On the day of surgery, a baseline neurophysiological testing, using both MMSE (T0) and QoR15 (Q0) scoring would be done at 7:00 am. No sedative premedication will be prescribed. After adequate fasting, the patient will be shifted to the operating theatre where monitors such as electrocardiogram, pulse oximeter, and non-invasive blood pressure cuff will be applied and intravenous (IV) access secured. At this time computer generated randomization table will be used to assign each patient to either the dexmedetomidine group (Group D, n=30) or placebo group (Group P, n=30). A 50 ml syringe containing dexmedetomidine 4mcg/ml in normal saline for Group D or normal saline for Group P will be prepared shortly before induction anaesthesia by an anesthesiologist, who will be the part of study but not involved in the perioperative management of these patients. The study drug infusion will be started by the same anesthesiologist soon after the securing the IV access. Group D will receive IV dexmedetomidine at the rate of 0.5 mcg/kg/hr until beginning of skin closure. Group P will receive volume matched saline.