3.1.1 What Are the Fundamentals of an Awake, Bronchoscopically Facilitated Intubation?
Awake bronchoscopic intubation, if it is to be performed rapidly and with minimal patient discomfort, requires an in-depth knowledge of the anatomy of the airway, adequate regional anesthesia, and dexterity with bronchoscopic manipulation. In order to achieve optimal regional anesthesia of the airway and avoid complications, a thorough knowledge of the local anesthetics employed and techniques of administration is necessary. The primary requirement for successful awake intubation is effective regional anesthesia of the airway.1
3.2.1 Why Is Knowledge of Upper Airway Anatomy Beneficial in Airway Management?
Knowledge of the structure, function, and pathophysiology of the upper airway permits the practitioner to anticipate potential life-threatening problems and better utilize the full spectrum of airway management techniques.2 Functionally, the upper airway can be considered to consist of the nasal cavities, pharynx, larynx, and trachea (see Figure 3-1).3 The oral cavity provides an alternate access route to the pharynx.
Sagittal view of the upper airway.
Anatomically, the nose can be divided into an external component and the nasal cavity.4 The external nose consists of a bony vault posterior superiorly, a cartilaginous vault anteriorly, and the lobule at the inferior-anterior aspect (see Figure 3-2).3 The cavity of the nose is divided into bilateral compartments by the nasal septum and continues posteriorly from the nostrils (nares), to communicate with the nasopharynx at the posterior aspect of the septum (the choanae) (see Figures 3-3, 3-4, and 3-5).3 The nasal vestibule is a small dilatation located immediately inside the nostrils.3,4 Each nasal cavity is bounded by a floor, a roof, and medial and lateral walls.3-5 The roof of the nasal cavity extends posteriorly from the bridge of the nose, and consists of the lateral nasal cartilages, the nasal bones and spine of the frontal bone, the cribriform plate of the ethmoid, and the inferior aspect of the sphenoid (see Figure 3-2).3,4,6 The nasal septum forms the medial wall, and is formed by the quadrilateral cartilage, the perpendicular plate of the ethmoid, and the vomer (see Figure 3-5).3 The lateral wall is formed anterior-inferiorly by the frontal process of the maxilla, the nasal bones anterior-superiorly, the nasal aspect of the ethmoid superiorly, and the perpendicular plate of the palatine and medial pterygoid plate posteriorly.3,7 A series of three horizontal scroll-like ridges (conchae or turbinates) project medially from the lateral walls of the nasal cavities, each of which overhangs a corresponding groove or meatus (see Figures 3-2, 3-3, and 3-4).3,8 Septal deviation is common, may be associated with compensatory hypertrophy of the turbinates, and ...