FE-NIV preparation
FE patients followed a standard preparation. Procedural sedation of intravenous midazolam 0.1-0.2mg/kg, ketamine 1-2mg/kg and atropine 0.01mg/kg was given to keep patient motionless yet still maintain spontaneous breathing. Topical anesthesia of 2% lidocaine solution, 1.0 ml/kg, was applied via syringe catheter into patient’s nostrils and trachea. A continuous oxygen flow (1.0 L/Kg/min, maximal 10.0 L/min) delivered through a small nasopharyngeal catheter as the “pharyngeal oxygen, PhO2”. PhO2-NC-AC technique was routinely used to ensure adequate oxygenation and ventilation during the entirety of FE procedure. Vital signs including heart rate, respiration, oxygen saturation and blood pressure were continuously monitored.
FE performed with a short working-length (30 cm) flexible endoscope, outer diameter 2.6 mm or 3.2 mm (Olympus, ENF-V2 or ENF-V3), without inner cannel. Flexible bronchoscope was introduced into the nasal tract and advanced into the supraglottic region. With chin lift maneuver, the entire larynx including the epiglottis, arytenoids, vocal cords and hypopharynx could be visualized. (Figure 1a) During nose-open phase, the posterior laryngeal commission and hypopharyngeal wall may appose each other and resulted a collapsed esophageal inlet.