The purpose of this study is to evaluate the effect of Intranasal Dexmedetomidine on hemodynamic responses to laryngoscopy and endobronchial intubation with a double lumen tube. Patients coming for elective lung surgery meeting the required inclusion criteria will be enrolled for this study. Information about the study will be conveyed and consent obtained in the preoperative period.

     Patients will be divided into two groups by computer-generated block randomization: Group A will receive Intranasal dexmedetomidine (1mcg/kg) diluted in 2 ml syringe and Group B will receive placebo (0.9 % saline) in 2 ml syringe in equal volume into both nostrils.

     Patients in pre induction room, after connecting to standard ASA monitors – ECG, Pulse Oximetry, Blood Pressure, study drug will be administered belonging to either Group A (Dexmedetomidine) or Group B (Placebo). 45 minutes after administration of the study drug, patients will be wheeled into Operating Theatre. After connecting standard ASA monitors, all patients will be induced with IV propofol upto 2mg/kg, fentanyl 1 mcg/kg, lignocaine 1.5mg/kg and vecuronium 0.1 mg/kg, in accordance with the current standard of care given in our hospital. Anaesthesia will be maintained with sevoflurane to get a MAC of 1 until tracheal intubation. After 3 minutes of mask ventilation, laryngoscopy and DLT insertion will be performed by an anaesthesiologist at the level of final year MD registrar or above. If the first attempt by the registrar is unsuccessful, subsequent attempts will be done by the senior anaesthesiologist posted on the list.

    Episodes of hypotension will be treated with a bolus of Ephedrine hydrochloride 3-6mg or Phenylephrine 25-50 mcg. Bradycardia will be treated with 0.3-0.6 mg atropine bolus. Any hypertension or tachycardia will be treated with additional doses of propofol and/or fentanyl. Systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), and heart rate (HR), will be recorded at baseline and regular intervals. All incidences of hypotension and bradycardia will be documented and the number of doses of rescue medication administered will be noted. The total laryngoscopy and DLT insertion time, total fiberoptic bronchoscopy time and total isolation time will be noted.