All the patients will be administered pre-induction fentanyl-citrate analgesia as per a predefined strategy (total 2-µg/kg IV: 1-µg/kg at 0 minute, 3-minutes time points]. Pre-oxygenation will be initiated at 6-minute time point or prior to that if there is a fall in oxygen saturation < 94 percent. At 9-minute time point anaesthesia will be induced with propofol 2-mg/kg and vecuronium bromide 0.08-mg/kg for skeletal muscle relaxation to facilitate tracheal intubation. Ventilator settings of CMV, tracheal tube size [7.5-mm I.D (male), 6.5-mm I.D (female)] and breathing circuit (circle-CO2 absorber system) will be the standardized in all the patients. Routine monitoring (EKG, NIBP, pulse oximetery, EtCO2) will be applied during the procedure as per the established practice. Over and above the use of study drug dexmedetomidine as per group allocation, propofol administration will be controlled with CLADS system tuned to consistent anaesthetic depth (BIS 40-60) in all the patients. In addition, all the patients will receive 0.5-µg/kg/hr fentanyl infusion during surgery. Oxygen.-air mixture (FiO2 0.50) will be utilized for intraoperative ventilation. Neostigmine (50-µg/kg) and glycopyrrolate (20-µg/kg) will be administered to reverse the residual neuromuscular blockade (non-depolariser).