 Because it is an invasive and uncomfortable medical procedure , intubation is usually performed after administration of general anesthesia and a neuromuscular @-@ blocking drug . It can however be performed in the awake patient with local or topical anesthesia or in an emergency without any anesthesia at all . Intubation is normally facilitated by using a conventional laryngoscope , flexible fiberoptic bronchoscope , or video laryngoscope to identify the vocal cords and pass the tube between them into the trachea instead of into the esophagus . Other devices and techniques may be used alternatively . 
