Use of a urinary catheter as a guidewire to facilitate safe nasotracheal intubation following iatrogenic retropharyngeal perforation

Summary

Nasotracheal intubation facilitates adequate access for surgical procedures in the oral cavity, is not limited by mouth opening and can be better tolerated by patients in intensive care. Complications of nasotracheal intubation can include epistaxis, turbinate injury and sinusitis. Retropharyngeal submucosal perforation by the tracheal tube has also been infrequently reported. Here, we report a case of difficult nasotracheal intubation resulting in retropharyngeal submucosal perforation in a patient with a history of obstructive sleep apnoea listed for uvulopalatopharyngoplasty. To facilitate successful tracheal re‐intubation, we used a soft urinary catheter via the other nostril. In this report, we discuss the reasons why this complication may have occurred, how submucosal perforation could be avoided, and reflect on our management of this rare complication. Difficult nasotracheal intubation can present unique challenges, and airway management plans should be made accordingly.

Introduction

Nasotracheal intubation facilitates surgical access for surgery of the oral cavity and upper airway and is well tolerated by patients [1]. It is used in oral, dental and cervical surgery and in some patients requiring long‐term mechanical ventilation. However, the incidence of complications exceeds that of orotracheal intubation, reaching up to 1.1% [2]. Recognised complications include epistaxis, turbinate injury, bacteraemia, sinusitis and even cranial fracture [3, 4]. Perforation of soft tissues by the tracheal tube is rarely reported. Here, we report a case of soft tissue perforation, with a tunnel formed beneath the submucosa of the retropharyngeal wall during difficult nasotracheal intubation, and discuss its potential causes and subsequent management.

Report

A 30‐year‐old man (height 162 cm, weight 78 kg) was admitted with a three month history of snoring and apnoeas whilst sleeping. He was diagnosed with obstructive sleep apnoea syndrome (OSAS) and scheduled for a uvulopalatopharyngoplasty under general anaesthesia. The patient was otherwise well with no history of comorbidity or prior surgery. Physical examination showed that his right nostril was more patent than the left. His maximum mouth opening was 6 cm and the thyromental distance was also 6 cm. His Mallampati score was two and his cervical range of motion was not restricted. The circumference of his neck was 41 cm. Pre‐operative nasendoscopy demonstrated a 100% collapse of the soft palate and 25% narrowing by Müller's manoeuvre, which is attempted forced inhalation by the patient with both the nose and the mouth closed while the nasendoscopy examiner observes the side‐to‐side and antero‐posterior narrowing of the pharyngeal walls [5]. The STOP‐bang score (based on snoring, daytime tiredness, observed sleep apnoeas, high blood pressure, body mass index, age, neck circumference, and gender) was five and the NoSAS score (based on neck circumference, obesity, snoring, age and sex) was 11, indicating a high likelihood of severe OSAS [6, 7]. The final diagnosis of OSAS was confirmed by an apnoea‐hypopnea index of six times per hour detected by polysomnography.

Prior to induction of general anaesthesia, the patient's nostrils were cleaned using moist cotton swabs dipped in diluted phenylephrine and lidocaine. General anaesthesia was induced with midazolam 0.05 mg.kg⁻¹, fentanyl 3 μg.kg⁻¹, propofol 2 mg.kg⁻¹ and cisatracurium 0.2 mg.kg⁻¹, After 3 min of manual facemask ventilation, the first attempt at nasotracheal intubation was conducted via the patient's right nostril with a polyvinyl chloride (PVC) tracheal tube (Well Lead Medical Co. Ltd., Guangzhou, Guangdong, China) with a 7.0 mm internal diameter and 9.6 mm external diameter. Substantial resistance was felt at a depth of 7 cm, so it was decided to switch to a tracheal tube with a 6.5‐mm internal diameter and 8.8‐mm external diameter (Well Lead Medical Co. Ltd., Guangzhou, Guangdong, China). When resistance was again detected at a depth of 7 cm, the tracheal tube was rotated 90 degrees anticlockwise and the resistance reduced significantly. The tracheal tube was then passed into the oral cavity and guided through the glottis via videolaryngoscopy (TDC series, Zhejiang UE Medical Corp, Xianju, Taizhou, Zhejiang, China). Some bleeding was then identified via videolaryngoscopy and it was recognised that the tracheal tube had perforated the retropharyngeal mucosa and exited the mucosa approximately 3 cm above the glottis (Fig. 1a). A flexible bronchoscope was not used for intubation.

Figure 1.

(a) Perforation of the retropharyngeal mucosa by a tracheal tube, exiting approximately 3 cm above the glottis (yellow arrow). Red arrow: epiglottis; blue arrow: tracheal tube. (b) A red urinary catheter (green arrow) was delivered through the left nostril to the lingual root. The tip of the urinary catheter was clamped by a sponge forceps and pulled out of the mouth to smooth the angle for the tracheal tube to follow.

We decided to use a urinary catheter with an external diameter of 4 mm (Suzhou XinDa Medical Equipment Co., Ltd., Suzhou, Jiangsu, China) as a guide wire to facilitate re‐intubation. The urinary catheter was lubricated and passed through a 6.5‐mm internal diameter tracheal tube and gently delivered through the left nostril to the lingual root. The tip of the urinary catheter was then clamped by sponge forceps, and pulled out of the mouth to smooth the angle for the tracheal tube to follow (Fig. 1b). With the guidance of the urinary catheter no significant resistance was felt, and the tracheal tube was delivered down the left nostril smoothly. Once the tube tip could be visualised in the oral cavity, the urinary catheter was released and withdrawn, and the tracheal tube advanced past the glottis under videolaryngoscopy. The exit point of the perforated tissue was compressed with gauze for 10 min. No excessive bleeding was observed. The surgery proceeded without difficulty. After the completion of surgery, the patient was transferred into the post anaesthesia care unit and his trachea was successfully extubated upon complete emergence from general anaesthesia.

Postoperatively the patient described a sore throat that was aggravated by swallowing, and was prescribed intravenous parecoxib 40 mg twice daily. His sore throat had resolved 48 h postoperatively. The patient was discharged on the third postoperative day with no complaints of sore throat or any other complications.

Discussion

We describe a case of retropharyngeal perforation during nasotracheal intubation of a patient who demonstrated few signs of predicted difficult tracheal intubation aside from the diagnosis of OSAS. According to Tintinalli and Claffey, perforation or rupture of parapharyngeal soft tissue is a complication that accounts for 2% of the total complications of emergency nasotracheal intubation under direct laryngoscopy [8]. A few similar cases have been reported, with retropharyngeal perforation identified by pharyngeal wall swelling or even neck distension [8, 9, 10, 11, 12]. In most cases the decision was made to secure the airway via orotracheal intubation and then examine the injury [10, 11]. The major concerns of retropharyngeal perforation include haematoma or abscess development in the false passages; excessive bleeding; subcutaneous emphysema; postoperative pain; hoarseness or dysphagia; and pneumoperitoneum [10, 13]. Here we identified the perforation upon seeing the tracheal tube tip inside the oral cavity. Since we did not identify excessive bleeding from exit of the perforated mucosa, and the surgery was essential to ameliorate his symptom of OSAS, we decided to continue with the surgery and chose to intubate from another nostril via the guidance of the soft urinary catheter. Our patient complained about local pharyngeal pain after the surgery, but fortunately he did not develop any other complications.

Anatomical variations can increase the risk of nasotracheal intubation complications. Patients with OSAS may present with altered anatomy of the retropharyngeal wall. The angle between the axis of nasal cavity and the pharyngeal wall may be steeper, therefore the tracheal tube must form a more pronounced curve to pass through the nasopharynx. Furthermore, OSAS may lead to swollen nasopharyngeal and retrophargyngeal mucosa which is susceptible to injury and perforation. Rotating the tube during intubation may be a useful technique under videolaryngoscopy. However, nasotracheal intubation involves passage through the nasopharynx that cannot be directly visualised by laryngoscopy. Rotating the tube during nasotracheal intubation may exert mechanical stress on the pharyngeal wall with risk of perforation.

There are many ways to facilitate nasotracheal intubation. For example, guiding the tube with a fibreoptic scope or other similar device can facilitate the passage of the nasotracheal tube. However, the lens of a flexible scope can be obscured by blood and secretions especially when mucosal injury occurs. We therefore chose a more cost‐effective and simpler tool to guide intubation. A urinary catheter has a soft texture which was appropriate to pass through the nasopharyngeal cavity without injuring the mucosa. A urinary catheter can also conform to a steeper angle (Fig. 1b), which if applied to fibreoptic scope or similar optical device, may damage the fibreoptic bundle within. An alternative to a urinary catheter could be a tracheal tube made of a softer material than a normal PVC tracheal tube since it would require less force to squeeze it through narrowed parts of the nasopharynx and retropharyngeal area.

Pre‐procedural preparation is important in nasotracheal intubation, particularly when the procedure may be difficult. Measures include thorough preparation of the nasopharynx with vasopressor agents such as phenylephrine to constrict the submucosal capillaries and minimise the risk of bleeding during airway instrumentation. Additional measures could include administration of an anticholinergic agent to reduce secretions, which may improve visualisation, particularly via a videolaryngoscope or flexible bronchoscope. Pre‐operative nasal computed tomography may be helpful to identify abnormal anatomy that may lead to a potentially difficult nasotracheal intubation.

On reflection, the retropharyngeal wall perforation observed in this case could potentially have been prevented. Firstly, when the first “hold up” occurred, the depth of the tube was merely 7 cm, indicating that the tip of the nasotracheal tube was at the retropharyngeal wall. When resistance was felt, the tip of the nasotracheal tube could have been visualised via a flexible bronchoscope via the other nostril to check what was hindering its advancement. Secondly, using flexible bronchoscopic nasotracheal intubation as the primary approach could have allowed more precise guidance of the tracheal tube. Thirdly, using a softer nasotracheal tube with higher plasticity could have reduced the pressure upon the mucosa. Finally, carefully measuring the angle between the nasal cavity and the retropharyngeal wall via the sagittal view of a nasal computed tomography scan may have provided more information to estimate the difficulty of nasotracheal intubation in this patient.

In this report, we presented an unusual case of submucosal retropharyngeal perforation during nasotracheal intubation. Using a urinary catheter as a guide for the subsequent attempt proved to be a practical and simple method to achieve atraumatic nasotracheal intubation.