Abstract

Airway management in patients with giant neck masses is usually a challenge to anesthesiologists. A giant neck mass could compress the airway and thus impede endotracheal intubation. We encountered a situation where the giant neck masses of a patient pushed the epiglottis posteriorly toward the posterior pharyngeal wall and compressed the laryngeal aperture narrowing after anesthetic induction, causing direct laryngoscopic intubation and sequential fiber-optic intubation failed. The neck masses twisted the aryepiglottic fold tortuously and clogged the laryngeal aperture tightly, making a flexible fiber-optic bronchoscope unable to pass through the laryngeal aperture. Later, we utilized a McCoy laryngoscope alternately to lift the compressed larynx up and away from the posterior pharyngeal wall, creating a passage and completing endotracheal intubation successfully with the aid of a gum elastic bougie. Our case suggested that the tilting tip blade of the McCoy laryngoscope could lever the tongue base up against the tumor mass compression to improve laryngeal views and facilitate endotracheal intubation when a difficult fiber-optic intubation was encountered on a compressed laryngeal aperture.

Keywords

Fiber optic technology; Intubation, intratracheal: difficult; Laryngoscopes: McCoy; Neck: mass;

1. Introduction

Difficult airway is a challenging condition for anesthesiologists, especially when it coincides with giant neck masses. Neck masses of different origins may distort the airway anatomy, making airway management difficult and endangering the patient’s safety.1, 2 Use of a fiber-optic bronchoscope has been considered to be an effective and safe method to intubate patients with difficult airway.³ However, fiber-optic intubation may become extremely difficult in the situation of a distorted airway, or when fiberscopic views are obscured, by e.g., massive hematemesis or plentiful sputum. When effective mask ventilation is guaranteed, direct laryngoscopy with a short acting muscle relaxant remains a practical option for tracheal intubation, even in patients with a potentially difficult airway.⁴ The McCoy levering laryngoscope has been well recognized as a useful tool for certain cases of difficult intubation.5, 6The advantages of the levering laryngoscope are that it improves direct vision of the larynx and expands the laryngeal aperture room when regular laryngoscopic forces could not elevate the epiglottis anymore.⁶ Herein, we report a patient whose giant neck masses narrowed the laryngeal aperture and defeated fiber-optic intubation, and who was successfully intubated by the McCoy laryngoscope with a gum elastic bougie in an emergency scenario.

2. Case report

A 71-year-old male was scheduled to undergo surgical excision for his large neck masses. He was 163 cm tall and weighed 61 kg. The masses were irregularly ovoid in shape, estimated at 12–16 cm in diameter, and circumvented his whole anterior neck (Fig. 1). He denied vocal hoarseness, dyspnea on exertion, or dysphagia. Neck computed tomography revealed tracheal deviation to the right, due to the external compression of the giant neck masses (Fig. 2). Preoperative airway examination showed a full mouth opening and adequate neck extension with a conclusion of Mallampati Class 2. Because of concern regarding the possibility of a compromised airway and difficult intubation, we informed the patient of the necessity of awake fiber-optic intubation via the nostrils. However, he strictly refused awake intubation out of fear, even though we advised him of the risks and even death. To comply with the request of the patient, the attending anesthesiologist attempted intubation under general anesthesia with direct laryngoscopy.

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Fig. 1. Giant masses located at the left anterior neck in (A) the lateral view and (B) the anterior view.

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Fig. 2. Computed tomography images of the upper airway showed (A) right-sided tracheal deviation and (B) the narrowest portion of the trachea (the arrow indicates absent narrowing of the tracheal lumen).

The patient was positioned in the sniff position, under standard monitoring. A fiber-optic bronchoscope, McCoy laryngoscope, and other airway instruments were available nearby in the operating room. His oxygen saturation was 99% on room air. After preoxygenation with pure oxygen for 5 minutes, anesthetic induction was done with intravenous fentanyl 100 μg, 2% lidocaine 40 mg, and propofol 140 mg. Manual breathing was adequately maintained by mask ventilation following the induction agents, and then succinylcholine 90 mg was given intravenously for muscle relaxation. Under complete muscle relaxation, direct laryngoscopic intubation with a Macintosh Number 3 blade (Welch. Allyn Inc., Onondaga County, NY, USA) was attempted. Despite the maximum lifting effort, the anesthesiologist could only see a drooping epiglottis. External laryngeal manipulation was impeded by his giant tumor. Several attempts of direct laryngoscopic intubation by two experienced anesthesiologists failed. Endotracheal intubation assisted with the backward, upward, and rightward pressure (BURP) maneuver on the larynx and a gum elastic bougie, fiber-optic intubation through the nostrils, blind intubation with a gum elastic bougie, and a combined approach of direct laryngoscopy and fiber-optic intubation were tried sequentially, but failed. The patient's neck masses hindered both the BURP maneuver and assistant jaw thrust. Fiberscopic examination disclosed that the neck masses pushed the tongue base downward, and the laryngeal structure and the epiglottis posteriorly against the posterior pharyngeal wall, thus obscuring the laryngeal aperture. Meanwhile, the encircling neck masses deformed the aryepiglottic fold tortuously and clogged the laryngeal aperture tightly, making the fiber-optic bronchoscope unable to pass through the compressed laryngeal opening. Occasionally, the flexible fiberscope was able to pass through the vocal cords, but frustratingly the endotracheal tube could not work its way beneath the glottis, due to tough resistance of the collapsed laryngeal structure. Finally we implemented a McCoy laryngoscope (Truphatek International Ltd, Netanya, Israel) to conduct intubation, utilizing its tilting tip to lever the collapsed larynx upward against the tumor's compression, to push the compressed lateral laryngeal walls outward, and to create an extra space to get a glimpse of the arytenoid cartilages. This key glimpse enabled us to probe the gum elastic bougie to the vocal cords and deliver an endotracheal tube into the trachea. No significant resistance was encountered while passing the endotracheal tube into the trachea and the correct tracheal tube position was confirmed by an auscultation and end-tidal capnography.

After the successful endotracheal intubation, general anesthesia was maintained with 3% sevoflurane in oxygen. Cisatracurium 10 mg was given sequentially for surgical relaxation. The lungs were ventilated at a tidal volume of 8 mL/kg and a rate of 12 breathes/minute; the peak airway pressure ranged from 18 mmHg to 22 mmHg. The perioperative course went uneventfully, and the patient was extubated under a full recovery from the general anesthesia. Postoperatively, he complained only of wound pain and a sore throat in the postanesthesia care unit, which were treated by intravenous morphine 5 mg. He did not have dyspnea postoperatively. Pathology of the neck tumors showed a papillary thyroid carcinoma with focal cystic degeneration. He recovered well from the operation without significantly adverse sequelae and was discharged on the 4^th postoperative day.

3. Discussion

Many cases of failed intubation occur when “difficult airways” are not recognized before the initiation of general anesthesia. A careful airway evaluation must be done and reassured routinely before an anesthetic induction. A difficult airway could be caused by any large neck mass, such as an enlarged thyroid tumor, or a deep neck infection, which produces a tracheal deviation, compression, or both. Bouaggad et al conducted a prospective study to evaluate the risk factors of difficult intubation in the presence of thyroid goiter, concluding that cancerous goiter and Cormack Grade III or IV were significantly associated with difficult intubation.⁷Cancerous goiter is usually associated with tissue fibrosis, which may immobilize the laryngeal structures and hinder the laryngoscopic views. In this case, postoperative pathology revealed papillary thyroid carcinoma. Therefore, the presence of a full mouth opening and adequate neck extension in the preoperative airway evaluation still cannot exclude a difficult intubation with conventional laryngoscopy. Furthermore, although the size of a goiter was not an absolute risk factor of difficult intubation,⁷ a giant neck mass itself could hamper the application of either the external laryngeal pressure, BURP maneuver or jaw thrust,⁸ and make it more difficult for anesthesiologists to obtain adequate laryngeal views.

Difficult tracheal intubation accounted for approximately 17% of adverse respiratory events for surgical patients in a closed-claims analysis, executed by the American Society of Anesthesiologists.⁹ The Difficult Airway Society has developed guidelines for management of difficult tracheal intubation in non-obstetric adults without upper airway obstruction.⁴ An increased incidence of morbid nonfatal events has also been noted in patients who have difficult tracheal intubation. Although several studies have predicted a difficult airway with variants predicting factors successfully, a wide disparity was discovered in the diverse sensitivities of the different models, which nevertheless resulted in occasional failure of predicting a difficult airway or difficult intubation beforehand.1, 7

According to the intubation difficulty scale, this patient did not actually fulfill many criteria of difficult intubation, such as inadequate month opening, limited neck extension, or unfavorable degree of Mallampati classification.¹ In addition, there was no tracheal narrowing found in the neck computed tomography. As the patient refused fiber-optic nasal intubation due to fear, we considered that conventional direct laryngoscopy may be feasible if the mask ventilation was secure.⁴ Unfortunately a conventional Macintosh laryngoscope blade could not lift the vallecula up, because the surrounding papillary carcinoma increased the soft tissue stiffness and anchored the laryngeal structure on the neighboring connective tissue. Also, the giant mass displaced the laryngeal structure further and pushed the epiglottis to a position where it blocked the laryngeal aperture, resulting in difficulty of fiber-optic probing. We expected that fiber-optic intubation would not become easier whether the patient was kept awake or sedated under intravenous anesthetics.

Awake fiber-optic intubation with a flexible fiberscope is the gold standard for an anticipated difficult intubation, especially when complicated with a compromised airway.10, 11, 12 In our patient, an alternative method using a levering laryngoscope was chosen instead of a flexible fiberscope, because the bronchoscope tip was blocked by the drooping tongue and distorted laryngeal anatomy. Additionally, the BURP maneuver and assistant jaw thrust were impeded by the giant neck masses. Asai and Shingu stated that the paucity of the normal anatomical space between the posterior pharyngeal wall and the larynx, was a typical reason to lose out endotracheal intubation when a flexible fiberscope was used.¹³ Furthermore, the fiberscope was not strong enough to guide an endotracheal tube into the trachea in the context of a severely distorted airway.¹⁴ Excessive force exerted during intubation may injure the glottic tissue or break the flexible bronchoscope.

The McCoy laryngoscope has been reported to improve laryngeal views in patients with difficult intubation.5, 6 The McCoy laryngoscope is designed to fulcrum its tilting blade tip within the pharynx and to concentrate the levering force of the blade tip right on the spot of the vallecula, thus the epiglottis can be effectively lifted away from the posterior pharyngeal wall to expose the larynx further, even against the overlying tumor’s compression.⁶The specific distribution and contour of the giant neck masses in this case was strongly associated with the lack of preoperative warning predictors of difficult intubation and unforeseen occurrence of epiglottis drooping and laryngeal aperture collapse. It was demonstrated in the patient presented in our report that the McCoy laryngoscope could facilitate successful intubation in an emergency situation, when facing a comatose patient whose airway is compromised with huge neck masses, or who rejects awake intubation (Fig. 3). The McCoy laryngoscope provides a crucial boost in improving the laryngeal view and helps to complete tracheal intubation in the situation of difficult fiber-optic intubation.

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Fig. 3. Algorithm of airway management for patients with giant neck masses. aIf the drooping tongue blocks the way of the fiberscope, we suggest elevating the obstacle with forceps, a blocker, or even the blade of a laryngoscope.

It is concluded that giant neck masses do not necessarily show adverse predictors during preoperative airway evaluation. Caution should be taken when difficult intubation could be encountered, due to a tortuously distorted airway, slumped tongue base and compressed laryngeal space after anesthetic induction. In a particular scenario of giant neck masses combined with a collapsed laryngeal aperture, the McCoy laryngoscope may be a useful tool in providing a levering force for raising the tongue base against tumor weight and offering an improved view of the larynx for facilitating endotracheal intubation.

Acknowledgments

Funding sources supporting the submitted work include the Department of Anesthesiology, E-Da Hospital.