Successful intubation of a difficult airway due to a large obstructive vocal cord polyp augmented by the delivery of a transtracheal injection of local anaesthetic

Abstract

We describe a case of a very difficult intubation which was safely navigated through careful planning. Our patient presented initially with increasing hoarseness and shortness of breath over a 6-month period. This was investigated and the patient was found to have a large vocal cord mass and was referred for urgent microlaryngoscopy and vocal cord polypectomy. On the day of surgery the obstruction was noted and awake fiberoptic bronchoscopy was used with a remifentanil infusion. Given the mass was large and increased in size with expiration, the time frame to pass the tube was extremely short. We delivered a transtracheal injection of local anaesthesia. This approach allowed for safe passage of the endotracheal tube. In patients such as this it may be worth considering the use of a transtracheal injection in the first instance.

Background

This case highlights a particular group of patients which will be very difficult to intubate. To be successful it requires careful preoperative planning and a technique which has been used effectively in patients such as fiberoptic bronchoscopy. Remifentanil is a potent ultra-short-acting selective μ-opioid agonist which precipitates analgesia and respiratory depression, it is faster acting and more potent than other drugs in this class such as fentanyl and alfentanil.¹ These properties make remifentanil ideal in managing difficult endotracheal insertions. This process is augmented by the use of transtracheal injection of lignocaine as it disperses evenly around the area and facilitates the action of remifentanil further. The use of transtracheal injection is not uncommon, its use is not widespread, and the benefits are demonstrated well in this unique case.

Case presentation

We report a case of a 52-year-old woman who presented to the ear, nose and throat casualty clinic with a 6-month history of breathing difficulties and increasing hoarseness in her voice. Medical history includes insulin-dependent type 2 diabetes, hypertension, dyslipidaemia, depression, gastro-oesophageal reflux disease and chronic kidney disease stage 3. The patient is a smoker with a 25-pack-year history, admits to recreational drug use including cocaine and marijuana and has a body mass index of 45 kg/m². Flexible nasendoscopy revealed a large mass arising from the left vocal cord with normal movements of both vocal cords. The mass moved with breathing and covered more than 80% of the glottic area (figure 1).

Figure 1.

The vocal cord obstruction with enlarge polyp.

Treatment

The patient was referred for an urgent microlaryngoscopy and vocal cord polypectomy. She was seen preoperatively in the nurse-led preassessment clinic and due to annual leave the patient was not seen until the day of surgery by an anaesthetist. On senior anaesthetic assessment the patient had good mouth opening, Mallampati grade 3 and a short neck with a reasonable range of movement but the difficulties of intubating were noted. Following discussions with the otorhinolaryngologists, consultant intensivist and a consultant anaesthetist the decision was made to proceed with the surgery. Planning for the procedure included fiberoptic intubation while the patient was awake. This was performed with the aid of an Oxford HELP pillow. The nasal cavity was anaesthetised with 10% lignocaine spray. Supplemental oxygen was delivered via a nasal catheter. The trachea was anaesthetised via transtracheal injection of 2 mL of 2% lignocaine. Low-dose target remifentanil was titrated to ensure the patient’s cough reflex was at a minimum. On fiberoptic bronchoscopy a large ball valve obstruction was seen on the posterior aspect of the left vocal cord, which seemed to increase in size on expiration (video 1). Moderate bilateral Reinke’s oedema was present. Bronchoscope was passed delicately under the mass during inspiration. A 6 mm ID cuffed armoured endotracheal tube was successfully railroaded over the bronchoscope (figure 2). Epinephrine 1:1000 was delivered to the base of the lesion which triggered an episode of ventricular tachycardia. The large polyp was excised at the base and sent for histology. Extubation was uneventful.

Figure 2.

The vocal cord obstruction as the surgeons are starting to operate with their instruments while the patient is intubated.

Video 1.

Download video file ^{(6.5MB, mp4)}

DOI: 10.1136/bcr-2015-210905.video01

The vocal cord obstruction increasing due to protrusion from below the vocal cord during expiration which seems like it is increasing in size during expiration and blocking the cord.

Outcome and follow-up

The patient recovered well postoperatively. Her breathing immediately improved, however, she reported that the hoarseness had only mildly improved in comparison to preoperation.

Discussion

There are a few key issues that are clinically significant with this case. Careful planning is essential in trying to intubate a patient with such a large glottic obstruction. To create a safety culture it is imperative to involve various members of the patients care to plan effective management keeping in mind good communication, flexibility in decision-making and time to re-evaluate the situation.² This case highlights the importance of good communication and decision making so when a difficult situation occurs a resolution can be found. Ideally the patient should have been seen before the day of surgery by an anaesthetist given the findings on flexible nasendoscopy. The rigorous preoperative checks at our hospital ensured the issue was brought to light. Planning for the procedure was important and involved discussions with the otorhinolaryngologists as well as the consultant intensivist and a consultant anaesthetist colleague before a consensus was made and only then proceeded with attempting intubation.

The use of fiberoptic bronchoscopy-assisted endotracheal intubation was essential in this case. There were other options but after discussing this case it was the only viable approach we felt we could use. We considered other methods, including jet ventilation strategies, but these methods could be potentially hazardous in this type of patient.

Even if you use low pressures you need a patent non-obstructed airway for the passive expiration phase. With the polyp looking like it was filling the larynx, the airway pressure could rise significantly, causing barotrauma during the expiration phase of jet ventilation even with low-pressure high-frequency jetting.³

From a surgical point of view, jet ventilation with or without a catheter is a possible option as it enables great access. In this case after discussions we would not have been happy, after debulking of the polyp then perhaps if surgical access was a problem we could have converted to this strategy.

The placement of a cannula in the cricothyroid membrane is helpful if oxygenation of the patient is a problem during an awake fiberoptic procedure. This method can be difficult depending on the anatomy but is increasingly recognised and often used in practice.⁴

Fiberoptic bronchoscopy-assisted endotracheal intubation is a recognised method of navigating an obstruction in the vocal cords. A recent case where a large tracheal tumour, covering 90% of the lumen, caused difficulties in endotracheal intubation after multiple attempts were safely navigated following the use of fiberoptic bronchoscopy.⁵ The case of a 19-year-old patient with Ludwig's angina highlighted the effectiveness of an awake fiberoptic bronchoscopy and the ability in securing the airway using this method.⁶

A recent literature review on fiberoptic bronchoscopy drugs concluded that there is good evidence supporting the use of one of the two drugs in procedures such as the present case, one of these being remifentanil.⁷ A randomised controlled trial looked at the effectiveness of remifentanil versus fentanyl and midazolam in 74 patients; patients treated with remifentanil tolerated the procedures better with a large majority experiencing no cough.⁸ In a case such as ours as the obstruction increased in size on expiration it would be further exacerbated if the patient was to become distressed and started to cough.

The ‘spray as you go’ technique would normally be used in cases where you were using a fiberoptic bronchoscope as this aids the remifentanil use.⁷ It is noted that introducing this form of spray is difficult to achieve in patients with critical obstruction.⁹ Transtracheal injection of local anaesthesia carries risks as the anatomy can be difficult to identify. A high level of topical anaesthesia with good patient acceptance is noted but it should be done by those with specialist training.¹⁰ In our case the spray as you go technique was not feasible. The window of opportunity to pass the scope was only a few seconds due to the size of the obstruction and that it increased in size on expiration. The risk of causing discomfort to the patient which would precipitate coughing was high and this is where delivering a transtracheal injection made the procedure much easier to tolerate. This allowed us to pass the endotracheal tube safely and uneventfully.

Using fiberoptic intubation in cases where the glottic opening is narrowed can allow successful passage. There are risks with this approach but these can be reduced by careful planning and management.

Patient's perspective.

• The whole experience was foreign to me in the beginning and quite surreal. On the day of surgery the team was very clear about the risks of anaesthetic and took time to explain things to me. I was given options and this helped to put me at ease. It was nice to feel involved. I was fully aware of what to expect and while it was daunting being awake for the beginning; once the procedure was over I felt quite good about everything that happened.

Learning points.

• If a patient like this is identified they need to have senior anaesthetic input prior to surgery.

• Careful anaesthetic planning and multidisciplinary discussions are essential before intubation.

• Remifentanil is effective in reducing cough reflex and can aid fiberoptic bronchoscopy.

• In an upper airway mass a transtracheal injection of local anaesthesia may be more suitable than the well-used spray as you go technique.