Awake fiberoptic intubation
Sometimes an indirect visualization technique becomes necessary, either dur-ing airway rescue, or when a pre-operative examination suggests a likelihood of difficult intubation.
In such cases, perhaps the most definitive technique is to secure the airway while the patient is still awake and breathing spontaneously. Awake fiberoptic intubation requires topical anesthesia for the patient’s com-fort, as well as to blunt the gag reflex that would prevent successful intubation of the trachea. All too frequently, secretions will smear the optics of the scope: an anti-sialogogue can be helpful.
Several nerves are involved in the sensation of the upper airway (Fig. 2.8). It is not much of a mnemonic, but try to remember a variant to TGIF (Thank God it’s Friday) namely TGIR: “Thank God it’s recurrent.” It’s lame, but perhaps just lame enough to be memorable! All but the first of these make up the gag reflex.
We anesthetize the posterior tongue and oro/nasopharynx by either spraying 4% lidocaine or having the patient gargle viscous lidocaine. Glossopharyngeal blocks also work well. We block the superior laryngeal nerves by injecting 1% lidocaine close to where the nerves penetrate the thyrohyoid membrane (Fig. 2.9).
The transtracheal block is accomplished by injecting 2–4% lidocaine directly into the tracheal lumen through the cricothyroid membrane (after confirming needle location by easily aspirating air). Be sure to point the needle toward the carina. You are very close to the vocal cords, which you do not want to damage with a needle pointed cephalad!
This technique is better tolerated with sedation, though the risk : benefit of potential airway compromise and aspiration – more likely with a numbed larynx – must always be taken into account.
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