Airway Considerations in Case of a Large Multinodular Goiter.

Patients with large goiters pose a great challenge to the anesthesiologist regarding securing the airway without compromising the safety of the patient. The technique of intubation depends on the choice and expertise of anesthesiologist. Awake fiberoptic intubation (AFOI) is the preferred technique. We present the case of large multinodular goiter with difficult airway in which AFOI was successfully used to secure the airway. Proper assessment, planning, and preparation for airway management should be done preoperatively to ensure patient safety.

INTRODUCTION

Goiter refers to abnormal enlargement of thyroid gland. The prevalence of goiter varies from 80% in areas of iodine deficiency (Southeast Asia, South America, and Africa) to 1%–4% in iodine-replete areas of developed countries.[1] Patients with large neck swellings pose airway challenges to the anesthetist as failed tracheal intubation can result in significant morbidity and mortality.[2] In cases such as large multinodular goiters, there is decrease in neck movements, decreased mouth opening, tracheal deviation, and compression.[3] In addition to endocrine and metabolic defects, the substernal extension of mass makes the airway management more difficult.[4] The invention of fiberoptic bronchoscope and the method of awake fiberoptic intubation (AFOI) is a milestone in the history of anesthesia to manage difficult airway. It is a technique which allows a flexible oral/nasal route to provide a clear visualization of vocal cords and subsequent passage of an endotracheal tube (ETT) into the trachea under direct vision. Here, we present the management of a case of a large multinodular goiter, with difficult intubation and extubation.

CASE REPORT

A 50-year-old female patient presented with a complaint of large midline neck swelling extending on both sides of the neck. The patient was apparently normal 8 years back when she started noticing a swelling in the midline of the neck. It was painless and progressive in nature. Initially, the patient had symptoms of palpitations. As the size of the swelling increased, the patient started having discomfort in breathing on lying down. She needed two pillows or lateral position to sleep. She also noticed hoarseness of voice 1 year back. The patient is a known case of hypertension for 9 years and was on regular medication. The patient had hysterectomy done under spinal anesthesia 8 years back.

On examination, the patient was obese (body weight - 90 kg). Blood pressure was 160/110 mmHg. Medical opinion was taken, and she was started on tablet atenolol (50 mg) with amlodipine (5 mg) for optimization before surgery. Examination of the neck revealed a midline swelling which moved with deglutition. It extended from one side of sternocleidomastoid to the other [Figures 1 and 2], superiorly extending till hyoid bone [Figure 3] and inferiorly retrosternal extension (fingers could not be insinuated behind the sternum). It measured 10 cm × 5 cm × 3 cm. On palpation, consistency was variable from soft to firm having multiple nodules with dominant nodule on the right side. No engorged veins were present over the swelling. No eye signs were present (indicating thyrotoxicosis). Lymph nodes were not palpable.

Figure 1

Extension

Figure 2

Right dominant nodule

Figure 3

Hyoid extension

Airway examination revealed receding mandible, decreased mouth opening (around two finger breadth), protruding teeth, large tongue, and mallampati Grade IV. Neck flexion was severely restricted with a normal extension. Indirect laryngoscopy was done by otolaryngologist which revealed overhanging epiglottis, anteriorly placed right-sided arytenoid, and vocal cords were not visualized.

The patient was on tablet carbimazole 20 mg, and thyroid function tests were within normal limits. Electrocardiography (ECG) was normal. Ultrasonography of neck showed diffusely enlarged thyroid gland with right lobe measuring 6.8 cm anteroposterior (AP), left lobe measuring 5.5 cm AP, and isthmus measuring 2.6 cm AP, with multiple nodules. Fine needle aspiration cytology of the swelling revealed features of colloid goiter along with cystic degeneration. Thyroid scintigraphy (which was done before starting tablet carbimazole) revealed toxic multinodular goiter with nodule having high technetium uptake, substantiating hyperthyroid status. Chest X-ray showed retrosternal extension with compression of the trachea [Figure 4]. Awake fiberoptic oral intubation was planned for the patient. Procedure for AFOI was explained to the patient, and written informed consent was taken.

Figure 4

Retrosternal extension

On the day of surgery, the patient was given injection glycopyrrolate 0.2 mg intramuscular) 30 min before shifting into the operating room. After shifting the patient on the operation table, multipara monitors were attached including ECG, noninvasive blood pressure, and pulse oximeter. Baseline values were noted. Pharynx was sprayed with lignocaine 10% spray. The patient was positioned in the semirecumbent position at 30° angle (by adjusting the Operation theatre (OT) table) to prevent desaturation due to tracheal compression in the supine position. Fiberoptic bronchoscope (FOB) (Karl Storz) was loaded with cuffed ETT no 7.0 after lubrication of the scope. Oxygen was attached to the respective port of the scope. The ovassapian airway was introduced into the oral cavity of the patient. FOB was introduced into the oral cavity through it and advanced. Pharyngeal structures were visualized which were severely crowded. The epiglottis was large and overhanging. It was difficult to negotiate the FOB below the epiglottis. As the laryngeal inlet was approached, converging of false vocal cords could be seen. Topical anesthesia with 1 ml of injection lignocaine 4% was given to prevent reflexes through “spray as you go” technique through drug channel of FOB. Slowly, the FOB was advanced, and true vocal cords could be visualized which were moving bilaterally. Another aliquot of 1 ml of injection lignocaine 4% was given at this point. After crossing the vocal cords (subglottic area), we gave another 1 ml aliquot. 4th aliquot was administered after visualizing the carina (tracheal). ETT was introduced into the trachea by railroading along fiberscope and positioned above the carina. FOB was removed. Correct placement of the tube in the trachea was confirmed by checking end-tidal carbon dioxide (Etco2) and bilateral air entry. Cuff was inflated and the tube was secured. Injection propofol 150 mg intravenous (I.V.), injection butorphanol 1 mg I.V., and injection vecuronium bromide 8 mg I.V. were administered. Anesthesia was maintained with O2, N2O, isoflurane, and maintenance doses of vecuronium bromide 1 mg every 30–40 min. The patient was monitored for pulse rate, blood pressure, ECG, and Etco2. The patient was hemodynamically stable throughout surgery. Postsurgically, in view of complication of tracheomalacia, extubation was postponed, and the patient was shifted to Intensive Care Unit. After 36 h, leak test was performed which was negative. The patient was fully awake, oriented and hemodynamically stable. She was maintaining SpO2 of 100% on oxygen. The trachea was extubated after adequate oropharyngeal suctioning.

DISCUSSION

Massive thyroid swellings pose a large challenge to anesthesiologists. WHO has classified goiter according to the size in which Class 0 - palpable mass within the neck structure, Class I - visible, palpable and undermines the curves and the neckline, Class II - a very large goiter with retrosternal extension that makes the tracheal deviation, compression of trachea, and esophagus.[4] Our patient comes under Class II type goiter.

Up to 45% of the goiter patients have substernal component.[5] Retrosternal goiter can be classified as Grade I: Above aortic arch; Grade II: Between aortic arch and pericardium; and Grade III: Below right atrium.[3] When the goiter is massive and retrosternal, it compromises the airway severely as it leads to tracheal compression and deviation in addition to compromise of other airway structures. In 2004, Bouaggad et al. conducted a study regarding prediction of difficult tracheal intubation in thyroid surgery. According to them, tracheal intubation was easy in 36.9% of cases, mild difficulty in 57.8% cases, and moderate to major difficulty was encountered in 5.3% of patients.[2]

Bouaggad et al. in their study have evidenced that there is increased incidence of difficulty in endotracheal intubation with tracheal deviation, compression, presence of dyspnea, mallampati Grading III and IV, and neck mobility <90°.[2] Our case fulfilled all these criteria. As failed intubation can be cause of morbidity and mortality,[2] it should be preassessed, and intubation possibilities should be planned beforehand.

Various techniques can be used to manage difficult airway in patient with goiter. If the size of thyroid swelling is small, airway examination is normal, and there is no tracheal compression or deviation we can proceed for a conventional airway management.[4] The concept of AFOI is not clearly defined, and it depends mainly on personal preferences.[6] Our patient was a case of large multinodular goiter, with airway difficulty and tracheal compression. Hence, we opted for AFOI to secure the airway. We did not plan a direct laryngoscopy in view of very difficult mask ventilation and intubation due to obesity, retrognathia, decreased mouth opening, protruding teeth, large tongue, mallampati Grade IV, large goiter causing decreased neck movements and dyspnea on lying down indicating tracheal compression. Tracheal compression could also be seen on chest X-ray. These could have led to a “cannot ventilate and cannot intubate” situation. In such conditions, lifting the thyroid mass or rigid bronchoscopy only can help to keep the airway patent.[7] Another option could be blind nasal intubation. Ovassapian et al. in 2005 have mentioned that multiple attempts lead to trauma and frequent unsuccessive blind intubations.[8] We did not plan tracheostomy in our case due to large goiter obscuring the trachea and even extending retrosternally. It is mentioned in literature that tracheostomy is difficult to perform in the presence of large and vascular thyroid gland.[9]

However, El-Dawlatly et al. have reported to have done tracheostomy in awake patient and inserted a reinforced armored tube to secure airway due to failed fiberoptic intubation in their case.[10] Another approach to secure airway in case where FOB fails is by using intubating laryngeal mask airway (LMA).[11] LMA can even be used to ventilate “difficult to ventilate patients” when FOB fails and before securing airway definitely by some other means.[10] Furthermore, it can be used to manage stridor.[12] Combitube is also been used in two cases to manage difficult airway.[13]

Another problem with massive goiter is that once the patient is sedated or anesthesia is induced, soft palate and epiglottis fall back onto the posterior pharyngeal wall obstructing the airway.[14] Hence, the airway visualization would become difficult as only minimal space would be left for maneuvering of the bronchoscope. Therefore, we decided that it would be beneficial to do FOB in an awake patient without sedation, and inducing anesthesia after intubation is accomplished. It should be highlighted at this stage that we performed AFOI in the semirecumbent position (30° angle of the table) to prevent respiratory discomfort as our patient was obese with large retrosternal goiter. Suhas et al. have reported a case of doing an AFOI in the sitting position in a case with huge goiter.[15]

It is proved that most appropriate candidates for AFOI are patients with potential intubation difficulties, which are anatomical in origin such as no visualization of vocal cords with conventional laryngoscope.[16] It also prevents bleeding and edema leading to higher success in airway management.[17] Considering difficult airway due to massive goiter and other airway considerations already stated, we planned AFOI for our patient by which we could intubate her successfully.

A huge goiter compressing over the trachea for a very long period can cause atrophy and erosion of tracheal rings. Risk factors predisposing to postthyroidectomy tracheomalacia include goiter for more than 5 years, preoperative recurrent laryngeal nerve palsy, significant tracheal narrowing or deviation, retrosternal extension, difficult tracheal intubation, and thyroid malignancy.[1] Postextubation, this can cause collapse of the trachea in AP direction leading to desaturation. This is usually a self-limiting situation as the strength of the tracheal wall is regained after pressure relief.[18] One study quotes extubation after 36 h to prevent tracheomalacia.[19] Hence, we electively kept our patient in an intubated state to prevent tracheomalacia and extubated her after 36 h after performing leak test.

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Conflicts of interest

There are no conflicts of interest.