Use of Oxygen Nebulizer for Preventing Post-operative Sore Throat

Inclusion Criteria: * Age 18-75 years * Pre-operative Hb \>10 g% or Hct \> 30% * American Society of Anesthesiologist (ASA) class I-III * Elective surgery * General anesthesia with oroendotracheal tube using Macintosh laryngoscope * Not exposed to intraoperative nitrous oxide * Oxygen saturation at room air \> 95% before induction and at arrival the PACU Exclusion Criteria: * Cases needing ICU admission immediately post-operative * Conditioning requiring post-operative oxygen therapy e.g. heart disease, pregnancy, morbid obesity, cardiac and thoracic surgery * Patients' conditioning affecting to complication of nebulizer oxygen therapy e.g. pulmonary disease, bleomycin treatment * Patient's conditioning affecting POST assessment e.g. pre-operative using ventilator, recent upper respiratory tract infection (URI), recent lower respiratory tract infection and history of difficult airway * Surgical conditioning affecting POST e.g. airway surgery, oral surgery, esophageal and neck surgery