The Difficult Airway in Adult Critical Care

Gavin G. Lavery, MD, FCARSCI, MB, BCh, BAO; Brian V. McCloskey, MB, BCh, FRCA, FFARCSI, MRCP


Crit Care Med. 2008;36(7):2163-2173. 

In This Article

Fiberoptic Intubation

Although comparative research in this field is rare, most experts agree that awake fiberoptic intubation is the technique of choice with an informed, prepared patient and a trained operator with appropriate equipment. The technique ensures that spontaneous respiration and upper airway tone can be maintained and has been extensively described by others.[78,79,80,81,82,83]

Adequate psychological preparation is essential. Numerous sedation agents have been evaluated, including benzodiazepines, opioids such as alfentanil or remifentanil, and intravenous anesthetic agents such as (low-dose) propofol infusion.[84] Supplemental oxygen should be provided, usually through the contralateral nostril. Care must be taken not to overdose the patient and to maintain spontaneous respiration throughout.

Topical anesthetic agents include lignocaine ± phenylephrine or cocaine. Cocaine has the advantage of producing vasoconstriction but has been associated with myocardial ischemia. Nebulized lignocaine can be used but may result in high blood lignocaine levels, coughing, and bronchospasm. Anesthesia of the vocal cords and upper trachea is usually provided by a spray as you go technique using 2% lignocaine. Another potential technique is superior laryngeal and recurrent laryngeal nerve blockade.[85]

Fiberoptic intubation is usually more straightforward through the nasal (rather than oral) route. The operator may stand either behind the patient's head or to the side, facing the patient. The vocal cords should be visualized and then lignocaine sprayed through the cords. The scope may then be advanced to the midtracheal level and the carina visualized. The ETT may then be placed carefully through the nasal cavity and into the trachea. Occasionally the passage of the ETT may be impeded by the vocal cords. Withdrawing the ETT, rotating 90o anti-clockwise, and readvancing usually resolves this problem. The presence of end-tidal carbon dioxide confirms tracheal position. The ETT should be positioned approximately 3 cm above the carina.


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