Airway management of a huge thyroid: A case report

K Senthil Kumar¹, N S Sushmithaa², J Sivagurunathan³, S Nirmal Kumar⁴, B. Anis⁵

¹Senior Consultant & Head, Anaesthesiology, Kauvery Hospital, Trichy

²Final year DNB Anaesthesiology, Kauvery Hospital, Trichy

³Consultant, Department of Anaesthesiology, Kauvery Hospital, Trichy

⁴Senior Consultant, Department of Anaesthesiology, Kauvery Hospital, Trichy

⁵Senior Consultant & Head, Surgical Oncology, Kauvery Hospital, Trichy

Abstract

Enlarged, and long-standing, thyroid swelling often leads to airway distortion and altered anatomy thereby making intubation a challenge to anaesthesiologist.

Here we report a case of long standing papillary carcinoma of thyroid with tracheal narrowing posted for Total thyroidectomy, who was intubated after airway anaesthesia using awake fibre optic bronchoscopy.

Key words: Huge Thyroid; Difficult airway; Fibreoptic Bronchoscope; Thyroidectomy

Background

Thyroid malignancies lead to changes in the airway, causing difficulties in intubation. Airway control may be difficult in such surgical procedures, due to large thyroidal masses compressing the trachea and the resultant non-visualisation of the opening of the glottis during conventional laryngoscopy. The thyroid mass in our case was exceptionally large and had distorted the airway anatomy.

The main reasons for difficult airway in thyroid patients are,

Anteriorly displaced Larynx
Tracheal deviation
Restricted neck movements
Difficult external manipulation during intubation due to neck swelling
Airway edema.

Fig (1): Huge thyroid swelling

A 50-year-old male patient, weighing 72 kg and of height 169 cm, who had diabetes, was evaluated in our outpatient clinic. He was a non-smoker and an occasional consumer of alcohol. He had a goiter that gradually increased in size over the past 8 years. The swelling started as a small swelling and progressed to present size. He has also noticed change in voice for the past 3 months. He was planned to undergo total thyroidectomy.

In the preoperative evaluation, neck examination showed an exceptionally large thyroidal mass and obviously trachea could not be felt (Figure 1). His Mallampati score was class III and his sternomental distance and thyromental distance could not be evaluated due to the neck mass. Routine blood investigations and surgical profile were done. Pulmonologist opinion was obtained and pulmonary function test was normal as per his reports. CT chest was done which showed narrowing of trachea, 4 cm below the vocal cord (Figure 2)

Fig (2): CT chest showing airway narrowing below vocal cord

Awake fibre optic intubation was considered in this patient due to his distorted airway. Patient and his family members were counselled regarding the airway difficulty he has and the procedure of awake fibre optic bronchoscopic placement of airway device was well explained, re assured and given confidence about the procedure.

Difficult airway cart in the operation room was prepared with a standard Macintosh laryngoscope set, a variety of face masks, airways, a fiberoptic bronchoscope, and tracheal tube introducer – a bougie and supraglottic airway devices were kept ready.

In the pre-operative holding area, patient was given antisialogogue, Inj Glycopyrrolate 0.2 mg IV 30 min prior to nebulisation. Then 4 ml of 4% lignocaine nebulisation was administered for 15 min so that the upper airway and to some extent lower airway gets anaesthetised. After shifting the patient inside operation theatre ECG, SpO₂ and non-invasive blood pressure monitoring were connected and monitored.

Inside operation theatre, Inj. Dexmedetomidine IV infusion was started to allay the anxiety of the patient and to induce mild sedation. Nasal decongestant, Oxymetazoline drops and Lignocaine nasal jelly wear applied in the left nostril. Fibreoptic bronchoscope was inserted and lignocaine was instilled through suction port of the bronchoscope and topical spray was performed at various parts such as laryngopharynx, at the level of vocal cords and below the vocal cords so that the airway below vocal cord is anaesthetised. Fibreoptic bronchoscope was removed after instillation of lignocaine. After 2 min, adequate topicalisation with local anaesthetic was ensured, then airway was secured using 7.5 mm flexometallic endo tracheal tube through fibreoptic guidance by rail roading technique (Figure 3).

Fig (3): Performing Awake Fibreoptic Intubation

Intubation was confirmed with end-tidal CO2 and auscultation. Then Inj Propofol and Muscle relaxants were given, anaesthesia was maintained with 50% O2 + 50% Air + Sevoflurane and Inj. Dexmeditomedine infusion. Surgery was performed for nearly 8 hr and specimen was removed. Due to prolonged surgery and airway handling patient was kept on ventilator support postoperatively for 6 hr. After achieving all the criterias for extubation and complete awakening, patient was extubated on post-operative day 1 after complete analysis of trachea. Extubation was also done under fibre optic bronchoscopy, as tracheal collapse and airway compromise was expected. Extubation was smooth and uneventful.

Discussion

Patient’s history and preoperative imaging studies gave us details of the vocal cord narrowing and necessitated the need of awake fibreoptic intubation. An awake fiberoptic intubation avoids tracheostomy. Tracheostomy was not planned in our case, because of the anatomical restrictions in the neck. This can prevent conditions like “can’t ventilate and can’t intubate” scenarios occurring after induction of anaesthesia due to a complete tracheal collapse.

After discussing the advantages and drawbacks of all procedures for management of the difficult airway, we managed the case with an awake fiberoptic intubation.

An awake extubation is as important as awake intubation in case of large goiters. Chronic, huge goiters cause tracheal cartilage erosion and tracheomalacia, which will be much evident after extubation. Hence, in our case extubation was also done with fibre optic bronchoscopic guidance.

Conclusion

In managing difficult airway, careful selection of choice of intubation technique should be done as per risk versus benefit of various available techniques based on available evidence-based studies. Proper preoperative airway assessment, preparation, timely decision and skilful management reduce the morbidity and mortality in difficult airway cases involving thyroid enlargement.

References

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