Sudden airway obstruction during emergence from general anesthesia in a post-radiation nasopharyngeal carcinoma patient with lower cranial nerve injury: A case report

Abstract

This article presents a case study of airway obstruction encountered during the post-anesthetic recovery period in a patient with nasopharyngeal carcinoma who had suffered cranial nerve damage subsequent to radiation therapy. It underscores the necessity for meticulous preoperative preparation during the induction of anesthesia and a comprehensive assessment coupled with careful preparation prior to extubation in the recovery phase. These measures are crucial to guarantee the safety of perioperative anesthesia in such patients. The case report is intended to contribute to the clinical knowledge base for anesthesiologists managing patients with nasopharyngeal carcinoma who have experienced post-radiation cranial nerve impairment. This case report has been meticulously crafted in compliance with the CARE (Case Reports) guideline, ensuring a standardized and rigorous approach to presenting the patient’s medical history, diagnosis, treatment, and outcomes.

Background

Nasopharyngeal carcinoma (NPC) is considered one of the most prevalent malignant tumors in China, with radiotherapy continuing to be the cornerstone of treatment.^1,2 Despite its therapeutic benefits, post-radiotherapy patients frequently grapple with a spectrum of systemic and localized side effects. These include temporomandibular joint dysfunction, soft tissue atrophy and fibrosis, radiation-induced osteomyelitis of the jaw, radiation myelopathy, and, particularly in advanced stages, the involvement of craniofacial nerves. ³ Collectively, these complications can exert a profound impact on respiratory function.^3–5

The repercussions are multifaceted, encompassing restricted mouth opening due to joint stiffness, which escalates the Mallampati airway classification; airway spasm and obstruction precipitated by oropharyngeal mucosal damage and bleeding; and dysphagia, weakened cough, and the risk of airway obstruction due to compromised cranial nerves, such as IX, X, XI, and XII. ⁶ The literature is replete with case reports highlighting the challenges of swallowing difficulties and temporomandibular joint stiffness and deformity in the aftermath of radiotherapy for NPC. ⁷ However, to date, effective strategies for improvement remain elusive. ⁸

The anesthetic management of patients with these post-radiotherapy sequelae undergoing general anesthesia poses a formidable challenge for anesthesiologists, ⁹ necessitating a nuanced and cautious approach to ensure patient safety and optimal outcomes. This case report has been meticulously crafted in compliance with the CARE (Case Reports) guideline, ensuring a standardized and rigorous approach to presenting the patient’s medical history, diagnosis, treatment, and outcomes. ¹⁰

Case presentation

A 64-year-old man, weighing 50 kg and classified as American society of Anesthesiologists physical status classification system, was diagnosed with NPC (CT3N2M1 [bone metastasis]) following a biopsy revealing “non-keratinizing undifferentiated carcinoma.” His treatment history includes four cycles of the TPF regimen (docetaxel, cisplatin, capecitabine), zoledronic acid for bone protection, and 32 fractions of radiotherapy. The patient also underwent immunotherapy with nivolumab and received supplementary radiotherapy to address bone metastases. The patient presented with recent symptoms of sore throat and dysphagia, prompting a visit to the Second Affiliated Hospital of Jiaxing University, on 12 February 2022, where they were preliminarily diagnosed with “difficulty swallowing 12 days after radiotherapy for NPC.”

Medical history

The patient’s medical history includes a chronic condition of hepatitis B, diagnosed over 10 years ago. Notably, there is no documented history of hypertension, diabetes mellitus, cardiovascular disease, or any surgical or traumatic injuries.

Physical examination findings

Airway assessment

The patient exhibited a Mallampati score of III (on examination, the soft palate and the root of the uvula are visible upon mouth opening). The patient exhibits restricted cervical spine mobility, with a head extension of approximately 20 degrees, a thyromental distance measuring 3.5 cm, and a mouth opening of approximately 2.5 cm.

Cardiac function

Heart auscultation revealed no pathological murmurs, and the patient was classified with a normal heart function grade II. The patient’s echocardiographic assessment demonstrated a left ventricular ejection fraction of approximately 55%. The electrocardiogram (ECG) was unremarkable, showing no signs of arrhythmia or conduction abnormalities.

Respiratory system

Lung auscultation was clear, with no adventitious sounds detected. The patient’s breath-holding test yielded a duration of 20 s.

Abdomen

The abdomen was soft, non-tender, and without signs of organomegaly or peritoneal irritation.

Edema

No peripheral edema was observed, which is important for assessing fluid status and potential complications.

Nasopharyngeal assessment

Postnasopharyngeal irradiation alterations

A neoplasmic protrusion is evident on the central and left lateral aspects of the nasopharyngeal vault, characterized by a copious purulent exudate on its surface, along with lymphoid hyperplasia at the base of the tongue. The mucosa of the epiglottis and laryngeal inlet presents with a smooth texture, and the vocal cords exhibit a smooth contour with preserved motility. The glottic closure is competent, and the mucosa of the bilateral piriform sinuses appears smooth without any evident neoplasms (Figure 1).

Figure 1.

Post-radiotherapy alterations in the nasopharyngeal region as observed via electronic laryngoscopic examination.

Imaging

Head computed tomography showed that after treatment of NPC, there was a flocculent soft tissue density shadow in the surgical area, the bilateral pharyngeal recess disappeared, and local skull base bone absorption and destruction. Soft tissue density shadows were seen in the bilateral maxillary sinuses and mastoids (Figure 2).

Figure 2.

Computed tomography shows flocculent soft tissue density after surgery of the patient’s skull base lesion.

Preoperative assessment

Considering the patient’s compromised airway due to the history of radiation and potential anatomical distortions, a careful preoperative evaluation was conducted. The strategy for airway management included planning for an awake intubation to mitigate the risks associated with difficult intubation. The anesthetic plan was tailored for the patient’s upcoming surgery, which encompassed resection of skull base and nasopharyngeal lesions, in conjunction with multiple sinus window procedures. This approach was designed to ensure the patient’s safety and facilitate optimal surgical conditions.

Anesthesia induction and surgical procedure

The patient was meticulously prepared within the operating room, with the establishment of intravenous access and ongoing cardiac monitoring ensured. At this juncture, the patient’s heart rate was recorded at 76 beats/min, and non-invasive blood pressure monitoring indicated a blood pressure of 132/72 mmHg. An ECG was unremarkable, showing no signs of abnormal cardiac rhythms. To optimize oxygen reserves, a 3-min preoxygenation protocol was administered with an oxygen flow rate set at 3 L/min.

Intravenous midazolam 2 mg and sufentanil 5 μg was administered for sedation. A volume of 1 mL of ephedrine (10 mg/mL) was applied nasally to constrict the nasal mucosa vasculature. Subsequently, a bronchoscopic examination was conducted under the guidance of a bronchoscope, with lidocaine sprayed for topical anesthesia in three separate applications, each separated by a 2-min interval. Following the administration of local anesthesia, the patient was subjected to awake orotracheal intubation via the oral cavity, under the guidance of fiberoptic bronchoscopy.

Following successful intubation, general anesthesia was induced with a combination of 20 μg sufentanil for analgesia, 100 mg propofol for sedation, and 30 mg rocuronium for neuromuscular blockade. The surgical team then proceeded with the resection of skull base and nasopharyngeal lesions, along with multiple sinus window surgeries. Controlled hypotension techniques were applied to reduce blood loss and improve surgical conditions, resulting in an estimated blood loss of 200 mL for the 2-h procedure.

The surgery was completed without complications, reflecting the effectiveness of the anesthetic management and the surgical team’s expertise.

Recovery process

After 75 min in the recovery room, the patient became fully alert, was responsive to commands, and exhibited good muscle strength. At this point, endotracheal suctioning was carried out, the endotracheal tube was smoothly extubated, and the patient was transitioned to oxygen therapy using a face mask. Throughout these procedures, the patient’s vital signs were carefully monitored and remained stable. Within 3 min, the patient exhibited signs of agitation, labored breathing, and ineffective coughing, accompanied by a decline in peripheral capillary oxygen saturation (SpO₂). A suction attempt was made without notable secretions being removed. Subsequently, SpO₂ dropped to 88% within 30 s. The patient was rapidly transitioned to non-invasive positive pressure ventilation with a tightly fitted mask delivering pure oxygen; however, there was significant airway resistance and impaired ventilation, with SpO₂ further plummeting to 75%. Urgent assistance was called for, and the anesthesia nurse was immediately instructed to prepare the difficult airway cart for potential intervention. With the support of the team, an experienced anesthesiologist endeavored to perform endotracheal intubation. Despite employing video laryngoscopy, the attempt was met with significant challenges due to laryngeal edema, which obscured the view and precluded the identification of the glottic opening, resulting in a failed intubation. During this critical period, the patient’s peripheral capillary oxygen saturation (SpO₂) alarmingly dropped to 7%. As mask positive pressure ventilation was persistently applied, the anesthesia nurse was swiftly directed to prepare for advanced airway management, including the readiness of a laryngeal mask airway (LMA), a cricothyrotomy kit, and a high-frequency jet ventilation setup, ensuring that all potential avenues for securing the patient’s airway were readily available. After the failure of mask ventilation, a size 3.5 Air-Q LMA was promptly inserted. However, ventilation via the LMA also failed, resulting in a precipitous drop in peripheral capillary oxygen saturation (SpO₂) to 0%. At this critical juncture, another experienced anesthesiologist made a last attempt at endotracheal intubation before proceeding with a cricothyrotomy. In the face of ongoing challenges, video laryngoscopy revealed a still compromised view, marred by the presence of bloody secretions and laryngeal edema. Following urgent suctioning to clear the airway, the glottis was barely visible. A second attempt at intubation was cautiously executed. Upon withdrawal of the stylet, the endotracheal tube met resistance and could not be advanced. With dexterous manipulation, the tube was rotated clockwise in three deliberate turns, successfully navigating it into place. The tube was then securely connected to the mechanical ventilator to initiate positive pressure ventilation with 100% oxygen. After close monitoring for 30 min, the patient was transferred to the intensive care unit (ICU) for escalated surveillance. Subsequent to this, a chest X-ray, conducted 2 h post-intubation, depicted the endotracheal tube in situ with pronounced and hazy bronchovascular markings throughout both lungs; notwithstanding, the hilum appeared normal in contour, dimensions, and location. On the same night, at 22:00, the patient was smoothly weaned from mechanical ventilation and the endotracheal tube was uneventfully removed. By the next day, the patient was in stable condition and was consequently transitioned to a general ward for continued recovery. One week after admission, the patient was discharged home with a favorable outcome (Figure 3).

Figure 3.

The chest X-ray demonstrates coarsened pulmonary markings with haziness.

Discussion

In this clinical scenario, recognizing the potential for a challenging airway, a deliberate decision was made to perform an awake intubation during the anesthesia induction phase. This preemptive strategy was successfully executed, thereby circumventing the risk of a critical airway crisis that might have emerged during the induction process, as highlighted in relevant literature. ¹¹ During the post-anesthetic recovery phase, the patient encountered airway obstruction following extubation. Despite the crisis being adeptly managed, ensuring that no profound harm befell the patient, this event suggests potential shortcomings in the anesthetic management protocol. A thorough review of the incident is warranted to identify areas for improvement and to refine future practices in airway management during the recovery period. The effects of general anesthesia on respiratory function among patients previously treated with radiotherapy for NPC remain insufficiently elucidated within the current medical literature. To date, no peer-reviewed case reports have specifically explored this clinical conundrum. Potential mechanisms for ventilatory dysfunction during the emergence from general anesthesia include (1) overuse of opioid medications. According to Chang’s review, ¹² the use of opioid drugs, particularly fentanyl, especially when administered intranasally, is one of the risk factors for reintubation during emergence from general anesthesia. (2) Mechanical stimulation during intubation and extubation, such as suctioning and extubation itself, can induce airway responses including coughing, bronchospasm, and hemodynamic fluctuations such as hypertension, tachycardia, and arrhythmias, potentially leading to cardiovascular and cerebrovascular events, and even life-threatening conditions. ¹³ Unplanned secondary intubation, occurring within 2 h post-extubation, is a highly undesirable event during the emergence phase of anesthesia. It can significantly prolong hospital stays for patients and is associated with an increased risk of perioperative mortality.^14,15 In this case, despite a prolonged recovery time, residual opioid effects were likely minimal. The patient did not exhibit coughing or bronchospasm but experienced complete upper airway obstruction, with persistent failure of mask and laryngeal mask ventilation.

Possible causes for the upper airway obstruction in this case include (a) laryngeal edema resulting from surgical stimulation and secretions^16,17; (b) involvement of the cranial nerves (possibly IX, X, XI, XII) leading to decreased muscle tone in the larynx, difficulty swallowing, weak cough, and airway obstruction.^18,19 The initial intubation failure during the rescue attempt may have been caused by (a) limited mouth opening due to joint stiffness, ²⁰ leading to an increased Mallampati airway classification and difficulty exposing the vocal cords; (2) blood-stained secretions potentially contaminating the video laryngoscope, resulting in a blurred view, where a standard laryngoscope might have been beneficial. ²¹

The anesthetic management in this case had its limitations. Although we conducted an awake intubation during the induction phase of general anesthesia, our approach during the recovery phase lacked the necessary prudence. We failed to fully appreciate the patient’s unique circumstances. Although the patient’s consciousness and muscle strength had returned prior to extubation, we did not adequately assess whether the laryngeal edema had subsided or consider the risk of upper airway obstruction due to impairment of the posterior cranial nerves. Consequently, the inadequate pre-extubation evaluation and insufficient preparation before extubation serve as critical lessons from this case. Concurrently with the aforementioned considerations, furthermore, during the management of this case, we deliberately avoided the use of glucocorticoids like methylprednisolone for edema reduction because of their potential to suppress the patient’s immune system while it is recognized that corticosteroids can be beneficial in the prophylaxis against glottic edema. Additionally, during the tracheal extubation process, the accessibility of the procedure’s reversibility was not evaluated, which was one of the contributing factors to the occurrence of difficult ventilation. To address the potential for airway obstruction during tracheal extubation, it is crucial to be fully prepared with reversible strategies. In such cases, the selection of an airway exchange catheter (AEC) for the endotracheal tube is recommended. The AEC, featuring a hollow rigid core, enables ongoing oxygenation, or jet ventilation, and even permits the possibility of secondary tracheal intubation should the need arise. Ultimately, in cases where there is a heightened risk of post-extubation airway complications, the decision regarding the timing of extubation must be deliberated with caution. In such scenarios, transferring the patient to the ICU with the tracheal tube in situ for continued mechanical ventilation on a ventilator may represent a more secure strategy.

Conclusion

This case report addresses the occurrence of sudden airway obstruction during the recovery phase of general anesthesia in a patient undergoing surgery for NPC complicated by post-radiotherapy injury to the cranial nerves. The principal clinical insight gleaned from this case underscores the necessity of a rigorous pre-extubation assessment coupled with meticulous preparation to safeguard patient well-being. Prior to extubation, it is essential not only to evaluate the patient’s level of consciousness and muscle strength but also to consider the resolution of laryngeal edema and the risk of upper airway obstruction due to cranial nerve involvement. In anticipation of potential airway emergencies, such as upper airway obstruction, prolonging resuscitation efforts and transferring intubated patients to the ICU for monitoring and treatment are considered prudent management strategies. Furthermore, when the patient’s condition is favorable, the administration of fast-acting corticosteroids can effectively prevent airway edema. Ultimately, the use of innovative tracheal tubes, like the AEC, has proven beneficial in the acute management phase during tracheal extubation, safeguarding the reversibility of the procedure.

Abbreviations

AEC

airway exchange catheter

ECG

electrocardiogram

LMA

laryngeal mask airway

NPC

nasopharyngeal carcinoma