Med Laser 2022; 11(2): 120-124  https://doi.org/10.25289/ML.2022.11.2.120
Successful use of C-MAC® video laryngoscope for unexpected severe airway narrowing during anesthesia induction in a patient with a moderate-sized laryngeal tumor
Sung-man Hong, Hee-yeon Sung, Bong-jin Kang
Department of Anesthesia and Pain Medicine, Dankook University College of Medicine, Cheonan, Republic of Korea
Correspondence to: Bong-jin Kang
E-mail: anebjkang@hanmail.net
ORCID: https://orcid.org/0000-0003-4736-797X
Received: March 21, 2022; Accepted: May 7, 2022; Published online: June 30, 2022.
© Korean Society for Laser Medicine and Surgery. All rights reserved.

This is an open access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted noncommercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract
Periglottic masses can be treated by laser excision, simple electrocautery, or wide excision, including neck dissection. Smooth induction of anesthesia and airway management is a challenge in these patients. There is limited published literature on the probable airway complications during anesthetic induction with significant variability and low predictability among patients. We report one case of unexpectedly severe ventilatory difficulty in a patient who developed recurrent vocal cord cancer. Through the analysis of this case, we stress the limitations of clinical prediction of airway compromise during anesthetic induction and discuss the usefulness of a video laryngoscope in this kind of emergency.
Keywords: Anesthesia; Airway management; Difficult airway algorithm; Periglottic mass; Laser surgery
INTRODUCTION

Periglottic masses are featured as tumors, polyps, or granulomas. According to the severity of disease or therapeutic purposes, various laryngeal surgeries such as laser resection, simple electrocautery, and major dissection of larynx and neck tissue can be performed.1

If we want a safe anesthetic induction for surgery of these masses, we should be prepared to have a deliberate approach to airway management due to the nature of their existence along the airway. That is, difficulties during mask ventilation or laryngoscopic maneuver for exposing the vocal cord could cause complicating problems such as hypoxemia secondary to hypoventilation, brain damage, and cardiac arrest. Furthermore, laryngeal masses could show varying clinical features according to their variable durations of mass growth, locations, sizes, and radiation history, adding challenges to airway management.2,3 Thus, anesthesiologists and surgeons as perioperative physicians should be highly familiar with diverse manifestations of this condition during induction.4

At present, airway management algorithms for unexpected and difficult airway situations during induction of healthy patients have been established.5,6 However, there are no specific guidelines dealing with patients who have been generally accepted as having difficult airways like laryngeal masses. The reason for the difficulty in establishing such guidelines for patients with anticipated difficult airway conditions includes the varying and unpredictable clinical nature of each condition.7,8

The authors experienced unexpected severe ventilatory difficulty during induction caused by aggravated airway narrowing in a patient who just seemed to have had a modestly narrowed condition of his vocal cord inlet. Along this case report, available studies reporting prediction factors related to this kind of adverse airway outcomes in patients with periglottic masses are reviewed to suggest helpful tips for preventing or solving problems. Specifically, we emphasize the importance of utilizing videolaryngoscope to cope with such an adverse situation.

The informed consent was obtained from the patient for publication of this case report and any accompanying images.

CASE REPORT

An 87-year-old male (155 cm, 42 kg) was admitted to our hospital with a five-day history of hoarseness and dyspnea. The patient was diagnosed with laryngeal cancer five years ago, for which he underwent radiotherapy, resulting in complete remission. Since then, he underwent laryngeal microscopic surgery twice for recurrent subglottic polyps. At the time of admission, endoscopic evaluation revealed a 1.5 cm mass on the right posterior vocal cord and slightly decreased mobility of both vocal cords (Fig. 1). Modified Mallampati classification was assessed as class 2. No serious structural abnormality inducing upper airway obstruction was detected in neck computed tomography (Fig. 2). The patient’s dyspnea was relieved following three days of oral steroid administration and bed rest. He was scheduled to undergo a laryngeal microscopic biopsy and a laser cordectomy. In the ward, pulse oximetry readings showed 98% with oxygen supply of 2 L/min via a nasal cannula.

Figure 1. This patient shows a small mass on the posterior side of right vocal cord. His vocal cords also showed decreased mobility. A, anterior.

Figure 2. Preoperative view of laryngeal computed tomography shows a protruding mass but the size of remaining lumen of vocal cord seems to be not so small. A, anterior.

In the operating room, the patient showed no signs of respiratory distress. The value of SpO2 was 98% at room air. He had hoarseness of voice. Based on these clinical features, we decided to perform an endotracheal intubation after injecting propofol and cisatracurium, although moderate difficulty was expected. After 3 minutes of preoxygenation, we administered propofol at 2 mg/kg, cis-atracurium at 0.2 mg/kg, and remifentanil at 0.05 μg/kg/min through continuous infusion. The patient’s spontaneous breathing disappeared at about 20 seconds after administration of anesthetics. However, initial controlled ventilation with bag and mask became very difficult unexpectedly. Oral airway insertion did not improve the condition of ventilation. One anesthesiologist then held the mask with both hands and the other anesthesiologist squeezed the bag. However, ventilation with bag and mask by these two anesthesiologists were also ineffective, suggesting possibility of severe narrowing at the level of vocal cord. We then immediately used a video laryngoscope (C-MAC®; Karl Storz, Tuttlingen, Germany) to attempt endotracheal intubation with cuffed 5.5 mm ID laser tube. Modified Cormack-Lehane classification grade was 2B under the videoscope.9 The first attempt failed due to obstruction at the level of vocal cord. The second attempt with cuffed 4.5 mm ID plain tube also failed. At this time, we just placed the tube immediately above the remaining small slit-like opening between the vocal cords and tried to ventilate the patient with 100% O2. We could see a little more increase in ventilation. SpO2 was maintained at around 95% to 96%. Finally, we inserted a 4.5 mm ID plain tube without cuff. The value of SpO2 was maintained at 100%.

Operation was commenced by inserting the suspension laryngoscope. Both vocal cords showed thickened and swollen appearance, leaving only a slit-like aperture (Fig. 3). The surgeon performed partial cordectomy using laser along with removal of granuloma-like mass. Tracheostomy was also performed in preparation for total laryngectomy a week later. The pathologic report showed squamous cell carcinoma in the resected vocal cord tissue.

Figure 3. Intraopeartive view of vocal cord shows edematous and thickened features. A, anterior.
DISCUSSION

Although there is a clinical severity scale for directing surgical decision in the field of laryngeal cancer,10 this kind of scale is inappropriate for predicting the grade of airway difficulty during anesthesia induction. At present, there is a remote possibility to predict the exact feature of difficulty for various etiologic conditions comprising anticipated difficult airways. Thus, it would be helpful if we can accumulate clinical experiences for each etiology amongst various conditions of anticipated difficult airways. Our case illustrates a rather unpredictable severity of airway difficulty in a patient with laryngeal tumor. Although laryngeal tumor is classified as a kind of anticipated difficult airway,7,8 there are only a few studies exploring predictable factors of airway difficulties for this condition.

In the present case, the patient showed airway related symptoms such as progressive dyspnea and hoarseness. However, dyspnea disappeared after admission with steroid treatment. Wong et al.3 have studied possible predictive factors by analyzing correlations between various clinical aspects and outcomes of difficult airway in patients with periglottic tumors. In their study, various kinds of airway devices such as conventional direct laryngoscope, videolaryngoscope, optical stylet, and fiberoptic bronchoscopes were used. As a result, dyspnea or voice change among airway related symptoms and the history of radiation therapy showed specificity of around 90%, meaning that those factors could ‘rule in’ the possibility of occurrence of difficult airway.11 However, in the same study, those factors showed only 15% to 35% value of positive predictive value (PPV), meaning low predictive abilities. These results seem to be based on the fact that the actual prevalence of difficult airways in the setting of laryngeal tumors is quite low.

Considering such limited knowledge base for predicting difficult airways in patients with laryngeal tumors, surgeons and anesthesiologists should be cautious about possible occurrence of difficult airway even though the probability of positive outcome is not high. Our case gives a hint that decreased mobility and thickened condition of vocal cords could be predictive factors. These factors were unknown previously.

In the past, when unexpected ventilatory or laryngoscopic difficulty persisted after all direct laryngoscopic maneuvers by anesthesiologists, rapid surgical or other invasive access to trachea should have been the next option. However, the unmet need to well manage difficult airways has been filled since 1990s by the development of videolaryngoscopes equipped with good quality.12 This new tool has given various aids in solving difficult airway situations.3,13 It has also replaced the need of using awake fiberoptic bronchoscopy or surgical airways.12,13 There is good evidence of using videolaryngoscope in priority in situations of difficult airways.3,12,13 In comparison with a videolaryngoscope, awake fiberoptic bronchoscope guided intubation can cause some complications. It can cause a suffocating sensation during its movement into the vocal cord inlet. It can also cause bleeding or mass breakage due to its inability of seeing size mis-match between the outer diameter of endotracheal tube and the inner diameter of remained vocal cord inlet.14 In our case, upon recognizing severe difficulty in ventilation, immediate videolaryngoscope helped us select an appropriate sized endotracheal tube under cooperative decision of the team. Further, it helped to achieve temporary improvement of ventilation by allowing the oversized endotracheal tube placed onto the narrowed lumen of vocal cord inlet.

Recently, further expansion of videolaryngoscope use has been developed with the introduction of new inhaler spraying atomic sized droplet of local anesthetics into the pharyngolarynx. It produces enough topical anesthesia to prevent nausea or discomfort during videolaryngoscopic maneuver, saving spontaneous breathing. Thus, awake videolaryngoscopic intubation could be performed safely with the maintenance of spontaneous respiration and airway muscle tone in comparable state to awake condition. If this technique becomes familiar to physicians and could be well performed to eliminate patient discomfort, it will be the next game changer.14,15

In conclusion, we report the successful use of videolaryngoscope for overcoming an unpredictable occurrence of difficult airway. Our case showed severe ventilatory and intubation difficulties due to aggravated narrowing in the vocal cord inlet. Airway symptoms such as dyspnea, voice change, vocal cord immobility, and swelling could be real predictors of airway difficulty, even though their PPVs are not so high. This implicates that cooperative preparedness of anesthesiologists and surgeons is important.

FUNDING

None.

CONFLICT OF INTEREST

No potential conflict of interest relevant to this article was reported.

AUTHOR CONTRIBUTIONS

Concept and design: BK. Analysis and interpretation: SH. Data collection: HS. Writing the article: HS. Critical revision of the article: SH. Final approval of the article: SH. Overall responsibility: SH.

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