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Case Reports: Case Report

Successful Assessment of Vocal Cord Palsy Before Tracheal Extubation by Laryngeal Ultrasonography in a Patient After Esophageal Surgery: A Case Report

Yamamoto, Natsuhiro MD*; Yamaguchi, Yoshikazu MD; Nomura, Takeshi MD, PhD*; Yamaguchi, Osamu MD, PhD*; Goto, Takahisa MD, PhD*

Author Information
doi: 10.1213/XAA.0000000000000601


Recurrent laryngeal nerve (RLN) dysfunction is one of the major complications after esophagectomy.1 As bilateral RLN paralysis can cause upper airway obstruction, early recognition of this complication before tracheal extubation is important.

Direct laryngoscopy is currently the standard method for diagnosing RLN paralysis, but this procedure can be uncomfortable for patients and may cause undesirable changes in vital signs. Ultrasonography (US) of the vocal cords is a noninvasive technique that is well tolerated. However, the indications and efficacy remain to be determined. We report herein the use of laryngeal US to evaluate vocal cord function in an endotracheally intubated patient. The patient provided written permission for publication of this report.


A 68-year-old man had undergone esophagectomy and lymph node dissection for esophageal carcinoma after chemoradiotherapy. Shortly after the end of surgery, the trachea was extubated in the operating room, but laryngeal stridor and dyspnea developed 5 minutes later. Direct laryngoscopy showed that both vocal cords were almost fixed in the midline. Bilateral RLN paralysis was assumed, the trachea was reintubated, and the patient was transferred to our intensive care unit.

Tracheal extubation was scheduled for postoperative day 2. Before extubation, vocal cord function was assessed by US in the spontaneously breathing patient. A 4- to 7-Hz convex transducer (Philips Sparq, Amsterdam, the Netherlands) was placed transversely on the thyroid cartilage with the neck slightly extended. Laryngeal components such as the laryngeal cartilages and vocal cords were clearly visualized (Figure 1). US revealed the absence of vocal cord opening even during deep breathing. Only passive vocal cord motion associated with thyroid cartilage movement was apparent (Supplemental Digital Content 1, Supplemental Video 1, These findings were consistent with persistent bilateral RLN paralysis.

Figure 1.
Figure 1.:
Ultrasonographic view of the vocal cords before extubation. The convex US transducer was placed above the thyroid cartilage. No vocal cord movement was observed during inspiration or expiration, suggesting bilateral recurrent nerve palsy. The endotracheal tube was not directly visualized, but the air column between the vocal cords (*) indirectly implies the presence of the endotracheal tube. TC indicates thyroid cartilage; VC, vocal cord.
Figure 2.
Figure 2.:
Direct laryngoscopic view of the vocal cords after tracheal extubation. During inspiration and expiration, the vocal cords were almost fixed in the midline. AEC indicates airway exchange catheter; VC, vocal cord.

We planned to confirm the diagnosis by direct laryngoscopy immediately after tracheal extubation. Before extubation, we introduced an airway exchange catheter (AEC) through the endotracheal tube into the trachea to allow administration of oxygen during subsequent direct laryngoscopy and to facilitate reintubation if needed. Immediately after removal of the endotracheal tube, direct laryngoscopy was performed. The findings were comparable to those obtained during laryngeal US, confirming the diagnosis of bilateral RLN paralysis. We reintubated the trachea with the aid of the AEC. Oxygenation was maintained during extubation, reintubation, and direct laryngoscopy. The patient underwent tracheostomy the same day and was transferred from the intensive care unit to the hospital floor the following day.


Adequate upper airway function is essential for successful tracheal extubation, but can be difficult to evaluate during endotracheal intubation. We used US to assess vocal cord movement before tracheal extubation. The findings were consistent with bilateral RLN paralysis (Figure 2). This finding led us to use an AEC and facilitated safe management during extubation and reintubation.

Direct observation of vocal cord movement by laryngoscopy or observation by fiberoptic laryngoscopy is a standard method to diagnose RLN paralysis in those patients with a native airway. However, the utility of these methods in intubated patients is unclear because the endotracheal tube interferes with the evaluation of laryngeal function. Oral and pharyngeal secretions also interfere with direct laryngoscopy. In addition, introduction of the scope can be uncomfortable in awake or only lightly sedated patients.

US is an evolving method for assessing the vocal cords. Successful detection of RLN palsy after thyroid surgery has been reported.2 Wong et al3 reported that the diagnostic accuracy for identifying postoperative vocal cord palsy was comparable between laryngeal US and direct laryngoscopy. They also showed that the true vocal cords were more difficult to visualize than the false vocal cords and arytenoids using US, but diagnostic accuracy did not differ significantly among these 3 landmarks. Laryngeal US also provided high sensitivity and specificity for identifying vocal cord paralysis in children,4–6 in whom direct laryngoscopy is more difficult to perform than in adults. However, all these reports included patients who were extubated and breathing through the native airway. A few reports have described the use of US in tracheally intubated patients. The US-determined width of the air column between the vocal cords during endotracheal tube cuff deflation correlated with the development of postextubation stridor.7 This value may thus serve as a predictor of postextubation stridor. This method differs from our evaluation method, in that a high positive airway pressure of 30 cm H2O and endotracheal tube cuff deflation are required.

In our case, laryngeal US allowed satisfactory evaluation of vocal cord function in the tracheally intubated patient. The absence of vocal cord opening during deep breathing strongly suggested bilateral vocal cord paralysis, and this finding led us to use the AEC during tracheal extubation. It might have been excessively invasive if we had used an AEC without preliminary evaluation, as AEC is uncomfortable for patients and carries a risk of airway injury. US provided adequate and important information about the risk of RLN paralysis before tracheal extubation.

The US findings correlated well with those of direct laryngoscopy performed after tracheal extubation. If the RLN function had been normal, laryngeal US would have depicted vocal cord opening even in intubated patients. By way of comparison, US view of another tracheally intubated patient with normal vocal cord movement is shown in Supplemental Video 2 (Supplemental Digital Content 2,

Our experience suggests that laryngeal US may be useful in assessing the vocal cord function of intubated patients before extubation. Further clinical experiences and investigations are warranted.


Name: Natsuhiro Yamamoto, MD.

Contribution: This author helped conceive and design the work; collect, analyze and interpret the data; and draft and write the manuscript.

Name: Yoshikazu Yamaguchi, MD.

Contribution:This author helped conceive and design the work; collect, analyze and interpret the data; and write and revise the manuscript.

Name: Takeshi Nomura, MD, PhD.

Contribution: This author helped interpret the data, and write and revise the manuscript.

Name: Osamu Yamaguchi, MD, PhD.

Contribution:This author helped write and revise the manuscript.

Name: Takahisa Goto, MD, PhD.

Contribution:This author helped write and revise the manuscript.

This manuscript was handled by: Hans-Joachim Priebe, MD, FRCA, FCAI.


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Supplemental Digital Content

Copyright © 2017 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the International Anesthesia Research Society.