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It is a useful block in providing topical anesthesia to the laryngotracheal mucosa innervated by branches of vagus nerve.
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Injection through the cricothyroid membrane results in the solution being spread onto the tracheal structures and coughed onto the more superior laryngeal structures.
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Air should be aspirated freely before injecting the local anesthetics.
Perspective
This block, like all airway blocks, can be useful in sedated, spontaneously ventilating, “awake” patients requiring tracheal intubation.
Patient Selection. Any patient is a candidate in whom it is desirable to avoid the Valsalva-like straining that may follow awake tracheal intubation (in which the patient is sedated and spontaneously ventilating).
Pharmacologic Choice. The local anesthetic most often chosen for this block is 3–4 mL of 4% lidocaine. When multiple airway blocks are administered, the anesthesiologist should be aware of the total dose of local anesthetic used.
Placement
Anatomy. Translaryngeal block is most useful in providing topical anesthesia to the laryngotracheal mucosa innervated by branches of the vagus nerve. Both surfaces of the epiglottis and laryngeal structures to the level of the vocal cords receive innervation through the internal branch of the superior laryngeal nerve, a branch of the vagus. The distal airway mucosa also receives innervation through the vagus nerve but through the recurrent laryngeal nerve. Translaryngeal injection of local anesthetic is helpful in providing topical anesthesia for both of these vagal branches because injection below the cords through the cricothyroid membrane results in the solution being spread onto the tracheal structures and coughed onto the more superior laryngeal structures ( Fig. 28.1 ).
