Adjuncts to Endotracheal Intubation (also see Chapter 42 )

Equipment to facilitate difficult intubation should be readily available wherever emergency airway management is performed. The particular equipment available depends on the preferences of the anesthesiologist; the usefulness of most special equipment depends more on previous experience than on any intrinsic properties of the device. Certain items deserve mention, however, because of their frequent citation as aids to management of difficult airways.

The gum elastic bougie, or intubating stylet, is an inexpensive and easily mastered adjunct for management of a difficult airway ( Fig. 63-6 ). The stylet is placed through the vocal cords under the guidance of direct laryngoscopy, with the endotracheal tube then advanced over it into the trachea. Placement of the bougie is easier than direct placement of an endotracheal tube both because of its smaller diameter and the ability of an experienced operator

Figure 63-5 This patient has been impaled by a tree branch in the vicinity of the sternal notch and will require more complex initial airway management. Inspection of the airway and subsequent intubation were accomplished by awake fiberoptic bronchoscopy after topical anesthesia and minimal systemic sedation.

Figure 63-6 The gum-elastic bougie.

The esophageal Combitube (Kendall Sheridan Catheter Corp., Argyle, NY) is a double-lumen tube designed to be placed blindly into the patient's mouth.^[32] The Combitube is designed to facilitate positive-pressure ventilation whether placed in the trachea or the esophagus. It is commonly used by paramedics as a backup for failed intubation in the prehospital environment; in many jurisdictions the Combitube is the sanctioned airway rescue device for failed rapid-sequence intubation. Because placement of the Combitube has been associated with esophageal injury, its use should be reserved for emergency situations.^{[33] [34] [35]}

The laryngeal mask airway (LMA) (LMA North America, San Diego, CA) is now familiar to most practicing anesthesiologists and appears in the ASA algorithm for management of a patient with a difficult airway. LMA placement is possible in most patients who cannot be intubated and will permit adequate oxygenation and ventilation, although it does not provide as effective a barrier to aspiration as a cuffed endotracheal tube does.^[36] The LMA can also be used as a guide for intubation. An endotracheal tube may be placed blindly through the LMA lumen into the trachea, or a fiberoptic bronchoscope may be used to guide the tube through the LMA. The standard LMA is not designed as an intubation aid and is difficult to remove after an endotracheal tube has been placed through it. The LMA-Fastrach is specifically designed to facilitate intubation. It is rapidly mastered and has a high success rate.^[37] The LMA ProSeal is a double-lumen device designed to accommodate a nasogastric tube. Whether this design lessens the risk of aspiration remains to be investigated, and the use of this laryngeal mask in trauma patients has not yet been studied.^[38]

Transtracheal jet ventilation through a percutaneous catheter attached to a high-pressure fresh gas source has been promoted as a technique for emergency ventilation and oxygenation, especially by Benumof,^[39] with cited complication rates as low as 29%. After initial successful placement the catheter may kink or pull out of the trachea with motion of the patient's head or neck. Jet ventilation through a malpositioned catheter can cause tension pneumothorax—this condition should be suspected whenever a patient deteriorates suddenly after jet ventilation.

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