Airway management of a difficult airway due to prolonged enlarged goiter using loco-sedative technique.

Appropriate airway management is an essential part of anesthesiologist's role. Huge goiters can lead to distorted airway and difficulty in endotracheal intubation. In this report, we present a case of a 67-year-old woman with a huge toxic multinodular thyroid swelling, gradually increasing in size for last 20 years, where trachea was successfully intubated. She had a history of deferred surgery in June 2007 due to inability to intubate, despite 5-6 attempts using different laryngoscopes, bougie, and stylet. Patient was re-admitted in December 2011 for the surgery and was successfully intubated this time with help of fiberoptic intubation using loco-sedative technique. Patient was electively kept intubated postoperatively in view of chances of tracheomalacia due to prolonged large goiter. She was extubated successfully on post-op day 2 after demonstration of leak around trachea following tracheal tube cuff deflation. The different techniques of managing the difficult airway in these patients are discussed.

INTRODUCTION

Enlarged thyroid gland can lead to compromised airway with difficulty in tracheal intubation. Amathieu et al. reported that the overall incidence of difficult intubation in thyroid surgery was 11.1%.[1] Fiberoptic intubation (FOI) has been reported successfully in patients with enlarged thyroids in a difficult airway situation.[23] We present one such case of successful intubation with help of fiberoptic bronchoscope (FOB) using loco-sedative technique in a female patient with huge goiter, where previous surgery was deferred because of inability to intubate.

CASE REPORT

A 67-year-old, 58 kg woman presented with complaints of gradually increasing swelling in front of neck for past 20 years. Patient had history of palpitation and anxiety 7 years before and was diagnosed to be hypertensive and hyperthyroid. She was put on tablets neomercazole 10 mg BD, verapamil 40 mg OD, olmesartan 40 mg OD, which she was continuing. She had no history of change in voice and no respiratory symptoms. She was diagnosed a case of multinodular goiter (MNG), advised surgery, and was admitted for the same in June 2007. Surgery was deferred as patient couldn't be intubated despite 5-6 attempts. Patient then defaulted and re-appeared in December 2010 with complain of recent difficulty in swallowing for 1 month. On examination, patient was conscious, co-operative. Pulse was 90/min and blood pressure 140/90 mmHg. ECG showed sinus rhythm. She had no stridor and no respiratory difficulty, even on lying down. The neck swelling was 30 cm × 15 cm × 10 cm in size, nodular, extending from lower jaw to below sternal notch [Figure 1]. The lower limit of the swelling was neither visualized nor palpable. There were no distended veins on chest.

Figure 1

Pre-operative photograph of the patient

The swelling did not move with deglutition. On palpation, it was firm, immobile, and the skin above it was free. Airway examination showed less than 2 fingers mouth opening due to a large thyroid mass obstructing mouth opening, protruding incisors; Mallampati score couldn't be determined due to restricted mouth opening, limited neck extension, and severely restricted neck flexion.

Indirect laryngoscopy revealed normal vocal cord mobility. Radiological examination revealed lateral displacement of the trachea to the right on antero-posterior view and no compression of trachea in lateral view [Figure 2]. CT scan showed huge MNG with retrosternal extension [Figure 3]. Free T3, T4, and TSH levels were in normal limits.

Figure 2

X-ray showing tracheal compression in A-P but not in lateral view

Figure 3

CT scan showing distortion of the larynx by goiter

In view of previous history, anticipated difficult mask ventilation due to huge size of the tumor and difficult laryngoscopy and intubation, fiberoptic intubation was planned for the patient under loco-sedative technique. Difficult airway management cart with rigid bronchoscope and jet ventilation was kept ready. A team of cardiothoracic surgeons and perfusionist were informed and were asked to be at stand by for a femoro-femoral cardiopulmonary bypass in the event of inability to maintain airway or a cardiovascular event. The procedure was explained to the patient, and written consent was taken. Patient was kept fasting for 6 hours for solids and 2 hours for water before OT. Anti-thyroid medication and anti-hypertensive were continued till morning of surgery. Ranitidine 50 mg was given with a small sip of water on night before and morning of surgery. No preoperative sedation was prescribed. The patient shifted to the OT. Standard monitors (ECG, pulse oximeter, and NIBP) were attached, and the baseline vitals were recorded. Inj. glycopyrrolate 0.2 mg i.v. was administered. Xylometazoline was instilled in both the nostrils for vasoconstriction of nasal passage to facilitate passage of fiberoptic bronchoscope (FOB) without mucosal injury. The patient's airway was anesthetized by application of lignocaine 2% jelly in the nostrils, lignocaine viscous 2% gargles, 4 ml of lignocaine 4% nebulization, and lignocaine spray (10%). Oxygen was administered via oxymask at a rate of 5 L/min. Patient was administered 2 mg midazolam and 60 mcg fentanyl i.v. to allay anxiety and for mild sedation. FOB was loaded with a 6.0 mm armored endotracheal tube. After explaining to the patient, the bronchoscope was inserted through one of the nostrils and advanced towards laryngeal inlet. Laryngeal and esophageal openings were visualized side-by-side with the laryngeal inlet on the right side. Patient was instructed to take deep breaths to facilitate identification of the airway. FOB could be negotiated through the vocal cords with difficulty because of airway distortion. The fiberscope was advanced and positioned above the carina. Lignocaine 2.0% was administered via the drug port of the FOB, as and when required, to facilitate passage of FOB. Endotracheal (ET) tube was then threaded over the FOB, and the FOB removed. Eighty mg propofol was administered prior to railroading the ET tube through the vocal cord to attenuate the laryngeal and tracheal reflex. The breathing circuit was attached, and the tube placement was confirmed by movement of reservoir bag and capnography [Figure 4a]. Sevoflurane inhalation was started. 150 mcg of fentanyl and 5 mg vecuronium were administered intravenously. The ET was firmly secured, and anesthesia was maintained with O2 in N2O and sevoflurane, vecuronium, and fentanyl. Total 400 mg lignocaine was given to the patient.

Figure 4

a) Patient after intubation b) photograph of the patient after surgery and extubation

Total thyroidectomy with cervical extraction of retrosternal goiter was performed. The patient remained hemodynamically stable throughout the procedure. Post-procedure, patient was not extubated in view of probable tracheomalacia. On postoperative day 2, after patient was maintaining blood gases on “T – piece trial,” tracheal tube cuff was deflated and leak test was performed. Leak was demonstrated around tracheal tube after deflation, so it was considered safe to extubate the patient. A trolley for emergency intubation with rigid bronchoscope was kept ready. Patient was extubated and kept in post-operative area for 24 hours before being discharged to ward [Figure 4b].

DISCUSSION

Difficulty with intubation may be caused by an enlarged thyroid gland producing tracheal deviation, compression, or both.[4] Amathieu et al. concluded that classical predictive criteria like mouth opening <35 mm, Mallampati III or IV, limited neck movements <80°, and thyromental distance were reliable predictors of difficult airway.[1] Induction of general anesthesia in such cases could be risky because it may precipitate complete airway closure and make mask ventilation and tracheal intubation nearly impossible. Pressure on trachea exerted by a long-standing neck mass could have caused laxity to the parts of tracheal wall, which can lead to complete collapse of the airway with muscle relaxation. FOI, which can safely and promptly secure the airway, has been recommended for the airway management in patients with difficult airways. In our case, there was history of failed intubation with traditional methods, patient had prominent incisors, restricted neck flexion, and extension and was Mallampati's class IV airway.

Malhotra and Sodhi[5] have reported a strategy for airway management of thyroid patients if preoperative assessment has increased concerns regarding the airway. The strategy included the following options: Inhalation induction with sevoflurane in the semi-supine or semi-sitting position, awake FOI, tracheotomy, or ventilation through a rigid bronchoscope. The utility and safety of performing tracheotomy in the awake patient with a large neck mass prior to induction of general anesthesia are debatable, due to the location of the huge mass and the displaced anatomy it produces.[6] Problems like failure to visualize the glottis, trauma, bleeding, and laryngospasm has been reported with FOI.[7] However, compared with inhalation induction, the risk of losing the airway is minimal.[2] Inhalation induction with sevoflurane was not an option as patient may obstruct her airway as she loses consciousness.[5] Also, over-sedation with the agent might lead to respiratory distress, and a ‘cannot intubate cannot ventilate’ situation might arise. Retrograde passage of an epidural catheter through the cricothyroid membrane and passage of a tracheal tube over the catheter from above,[8] or introduction of a trans-tracheal cannula was also an option[9] but was discarded due to large thyroid mass and indistinct anatomical landmarks. Due to the airway problems encountered with thyroid disease, thyroidectomy under local anesthesia was advocated by some anesthesiologists.[10] However, a patient with huge thyroid causing compromised airway is a major limiting factor for this technique too.

Use of cardiopulmonary bypass for maintaining tissue oxygenation has also been described in cases of difficult airway with huge, compressive thyroid masses where airway maintenance was difficult.[11]

The safe options of airway management left in our case were as follow: Awake FOI or ventilation via rigid bronchoscopy. Ventilation through a rigid bronchosope is more helpful in patients with mid to lower tracheal obstruction and when endotracheal intubation is not possible.[6] Emergency femoro-femoral bypass was kept as a backup plan in event of severe airway compromise or cardio-respiratory event. The most viable option left in our case was fiberoptic intubation. Eldawlatly et al.[12] reported a case of an obese female with huge goiter presenting with difficult airway where the trachea was successfully intubated using FOB and loco-sedative technique. Local anesthesia was established using 5% lignocaine paste on the posterior third of the tongue along with lignocaine nebulization to oropharynx using 4% lignocaine. Intravenous sedation consisted of midazolam 2 mg and sufentanyl 5 mcg. The combined use of local anesthesia and mild sedation provided with a calm relaxed patient and a smooth intubation without significant respiratory compromise. However, this technique too is not free of flaws. Complete airway obstruction during awake FOI has been reported in whom the use of local anesthetic precipitated acute loss of the airway, so that urgent surgical intervention was required.[7] Also, in patients with pre-existing stridor and respiratory compromise, even mild sedation or sedative premedication is avoided to prevent further compromise.[2] Our patient was not having any previous respiratory compromise, so opting for mild sedation was considered better than having an anxious and irritable patient. Evaluating all the pros and cons, we decided to go for the loco-sedative technique for FOI. Loco-sedative technique is the use of local anesthetics for desensitizing the airway, and sedatives are given in sub-anesthetic doses for mild analgesia and sedation. We used lignocaine 4% and lignocaine 10% for anesthetizing the airway. Midazolam, fentanyl, and propofol were used as sedatives. The patient tolerated the procedure well.

Patient was electively kept intubated for 36 hrs in view of chances of tracheomalacia. She was extubated after cuff deflation demonstrated adequate leak around the tracheal tube while the patient was awake and breathing spontaneously.[13]

CONCLUSION

In conclusion, awake FOI using loco-sedative technique is a viable option in selected group of patients having compromised airway. Preoperative airway assessment could predict patients with possible difficult airway. Proper planning and discussing the problems with the patient and surgeon are important for safe outcome.