Effects of Adding Different Drugs for Preventing Cough Induced by Bronchoscopic Spraying of Local Anesthetics

After intravenous anesthesia is stabilized with BIS levels between 50-70, Intravenous lidocaine 1.5 mg/kg, or alfentanil 10 ug/kg, or 5 mL normal saline will be injected. Bronchoscopic insertion will be started 1 minute later. After seeing the vocal cords, local spraying of 2% will be initiated from vocal cords, trachea, and bilateral bronchial trees.