Patient preparation
All FE’s were performed at bedside of neonatal intensive care unit (ICU) or Pediatric ICU. Procedural sedation was administered with intravenous midazolam (0.1-0.2mg/kg) with or without ketamine (1-2 mg/kg) while maintaining spontaneous breathing. Topical anesthesia of 2% lidocaine solution (1-2 ml/kg) was applied via ET into distal airways. For infants without ET or just extubation, the lidocaine solution was applied into nostrils, larynx and tracheal lumen with a syringe catheter (a trimmed suction catheter attached to a 5-ml syringe) under rigid laryngoscopy. Continuous vital signs, including non-invasive blood pressure every 5 minutes, were monitored throughout the FE-NIV procedure.