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Laryngeal and Tracheal Injury
Case Synopsis
A 58-year-old, 50-kg woman presents to the operating room for total abdominal hysterectomy. After intravenous induction of general anesthesia, direct laryngoscopy is performed, yielding a view of only the arytenoids with the application of cricoid pressure. A single-use, coude-tip bougie is passed blindly until a positive hold-up sign is obtained, after which a 6.5-mm endotracheal tube is passed over the bougie into the trachea. Endotracheal placement of the tube is confirmed by capnometry. The surgery proceeds without incident. After taking down the drapes at the end of the surgery, diffuse subcutaneous emphysema is discovered over the torso with tracking up to the neck. Bronchoscopy performed before emergence from general anesthesia reveals a longitudinal tear in the membranous portion of the trachea extending into the right mainstem bronchus.
Problem Analysis
Definition
Injuries to the larynx and trachea can occur during laryngoscopy and endotracheal intubation, as well as after varying periods of time with an endotracheal tube in place; a selection of clinically relevant injuries is presented in Table 152.1 . These conditions range in severity from self-limited to requiring extensive surgical repair. Acute injuries are most likely related to direct trauma during endotracheal intubation. Reported traumatic injuries have been attributed to the laryngoscope (both classic direct laryngoscopes and videolaryngoscopes), single-lumen and double-lumen endotracheal tubes, the endotracheal tube stylet, the intubating bougie, and laryngeal mask airways.
TABLE 152.1
Examples of Clinically Relevant Injuries to the Larynx and Trachea Classified by Time Course
| Injury During Placement of Endotracheal Tube | Injury During Short-Term (<24 Hours) Intubation | Injury During Long-Term (>24 Hours) Intubation |
|---|---|---|
| Vocal cord hematoma or laceration | Vocal cord and laryngeal edema | Vocal cord and laryngeal granuloma or ulceration |
| Luxation of arytenoid cartilage | Vocal cord paralysis | Laryngotracheal, subglottic, or tracheal stenosis |
| Hypopharyngeal perforation | Tapia syndrome (temporary palsy of ipsilateral recurrent laryngeal and hypoglossal nerves) | Laryngeal mucosal ulceration and submucosal hemorrhage |
| Tracheal laceration, perforation, or rupture | Tracheal edema or hyperemia | Tracheal ulceration |
| Carinal or bronchial laceration or perforation | Tracheomalacia | |
| Tracheoesophageal and tracheoarterial fistula |
Injuries from prolonged intubation are more likely to be ischemic in nature and related to contact between the endotracheal tube, especially the cuff, and the tracheal mucosa. The trachea has a segmental blood supply, with perforating vessels feeding a submucosal plexus, which then perfuses the cartilaginous rings. Prolonged compression of the submucosal plexus causes ischemia to adjacent rings. Compression is most commonly attributed to an overinflated endotracheal tube cuff exerting a pressure of greater than 25 to 30 mm Hg on the tracheal mucosa. Ischemia will first lead to the development of edema and then progress to ulceration or granuloma formation. If allowed to continue unchecked, the ischemic damage will lead to the development of erosion through the trachea and the possible development of tracheoesophageal or tracheoinnominate fistulas. After removal of the endotracheal tube, severe injury may result in tracheomalacia, or less severe damage will heal by secondary intention, over the course of 3 to 6 weeks, and will lead to the formation of stricture, causing stenosis of the trachea.
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