Local/Topical Anesthesia of the Airway
I. Topical anesthesia of the airway
Aerosolized 4-5% lidocaine, about 5 ml over about 15 minutes.More effective after glycopyrrolate dries the airway mucosa.
May provide topical anesthesia, from nose to carina, that is satisfactory for fiberoptic intubation.
Less effective if inflammation, secretions.
II. Superior laryngeal nerve (SLN) blocks + transtracheal topicalization
SLN block:
SLN block blocks sensation from the superior larynx above the vocal cords (and paralyzes the cricothyroideus muscle). The block may be achieved by injecting 2 ml of 2% lidocaine just deep to the lateral thyrohyoid membrane bilaterally.
Transtracheal topicalization:
Topical anesthesia of tracheal mucosa mainly below the vocal cords may be achieved by injecting 4 ml of 2% lidocaine through the cricothyroid membrane and allowing the patient to cough.
III. Glossopharyngeal (IX) nerve blocks (e.g., for awake DL)
Blocks posterior third of tongue and tongue side of epiglottis. Inject 2 ml of 2% lidocaine into base of anterior tonsillar pillar (palatoglossal arch) bilaterally.