|Year : 2019 | Volume
| Issue : 2 | Page : 93-95
Dynamic ultrasound assessment of airway: A novel approach in a patient with goitre
Debendra Kumar Tripathy, Bhavna Gupta, Anup G Patil, Atif Khan
Department of Anaesthesia, AIIMS, Rishikesh, Uttarakhand, India
|Date of Web Publication||28-Aug-2019|
Dr. Bhavna Gupta
Department of Anaesthesia, AIIMS, Rishikesh, Uttarakhand
Source of Support: None, Conflict of Interest: None
A 31-year-old female with bilateral neck swelling causing tracheal narrowing and deviation of trachea to the left side was posted for total thyroidectomy. Long standing thyroid swellings with or without associated airway compromise are a challenge for anaesthesiologists to secure the airway. Because of the thyroid swelling, there may be deviation of trachea and/or compression of the trachea. Here we present a case of long-standing goitre with tracheal deviation and compression of trachea at the level of 2nd tracheal ring. Securing the airway in such cases poses a great challenge requiring meticulous planning and skillful experience. Careful preoperative evaluation and preparation in the form of clinical and radiological assessment is essential in formulating a plan of anaesthesia. Though static assessment is always important and helps in deciding the plan of management, conventional parameters may not be true in all cases such as in ours. Dynamic assessment may help the anaesthesiologist in deciding airway management in such cases.
Keywords: Difficult airway, dynamic assessment, goitre, ultrasound of airway
|How to cite this article:|
Tripathy DK, Gupta B, Patil AG, Khan A. Dynamic ultrasound assessment of airway: A novel approach in a patient with goitre. Airway 2019;2:93-5
|How to cite this URL:|
Tripathy DK, Gupta B, Patil AG, Khan A. Dynamic ultrasound assessment of airway: A novel approach in a patient with goitre. Airway [serial online] 2019 [cited 2020 Jul 16];2:93-5. Available from: http://www.arwy.org/text.asp?2019/2/2/93/265621
| Introduction|| |
Thyroid surgery poses multiple challenges to attending anaesthesiologists of which safe airway management holds primary importance. Large and long standing goitres are likely to present with tracheal narrowing and compression. The compression of trachea revealed on X-ray in our patient was confirmed with CT scan. Later, dynamic assessment was done using ultrasonography. The thyroid swelling was moved and the change in tracheal dimension was noted using ultrasonography. Ultrasound of the airway helps not only to localise the tracheal narrowing but also ascertains the extent of narrowing. It also gives information of change in tracheal diameter (improvement or worsening) on displacement of the thyroid swelling.
| Case Report|| |
A 31-year-old female was posted for total thyroidectomy in view of bilateral colloid goitre. The swelling was present for the past 10 years and was gradually increasing in size. She did not have any symptoms of dyspnoea, dysphagia, platypnoea, breathlessness or stridor. Ultrasound examination of the neck done by a radiologist suggested bilaterally enlarged thyroid glands with the right and left lobes measuring 2.8 cm × 4.7 cm × 6.2 cm and 2.5 cm × 4 cm × 5 cm respectively. Multiple heteroechoeic nodules were identified, and the trachea was compressed between enlarged lobes with no retrosternal extension. Airway examination revealed a short and thick neck, with visible midline swelling extending on both sides of the neck, limited extension and modified Mallampati Class II. X-ray of the soft tissue neck suggested tracheal deviation to the left side and narrowing [Figure 1]. Indirect laryngoscopy revealed bilateral mobile vocal cords with an adequate glottic chink.
|Figure 1: Anteroposterior and lateral neck X-rays showing narrowing of trachea with deviation of trachea to the left|
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Ultrasound of the neck was performed by an anaesthesiologist in the operation theatre with a LogiQ portable ultrasound machine (GE Medical Systems Co Ltd.). Both sagittal and transverse scans of the neck were done using linear probe (L35, 7.5 MHz). In the transverse scan, the tracheal diameter at the level of cricoid was 1.98 cm. The trachea was narrowest at the level of the second tracheal ring where it measured 0.78 cm. The thyroid swelling was then displaced laterally, initially towards the right (same side as the goitre) and later towards the left (opposite to the goitre), keeping the probe at the same level, and the tracheal dimension was found to be 0.65 cm and 0.95 cm respectively [Figure 2]. On lifting up the thyroid, there was no change in tracheal diameter. Sagittal scan revealed tracheal deviation towards the left with no retrosternal extension.
|Figure 2: Ultrasound image of the trachea using LogiQ portable ultrasound machine (GE Medical Systems Co Ltd). (a) Tracheal ring with marked inner and outer demarcation of trachea with measured diameter of inner trachea in neutral position being 0.78 cm. (b) Inner diameter of trachea measured 0.65 cm when trachea displaced to the right side (same side as goitre). (c) Inner diameter of trachea measured 0.95 cm when trachea displaced to the left side (opposite side to the goitre)|
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General anaesthesia was induced with injection fentanyl and propofol. Succinylcholine was administered after checking the ability to mask-ventilate, and intubation was performed with a size 7.0 mm internal diameter flexometallic tube after displacing the trachea towards the left. Following intubation, bilateral air entry was confirmed and the tube was fixed.
| Discussion|| |
Patients with thyroid swellings are a challenge to the attending anaesthesiologists. These patients may pose an anticipated difficult airway in the form of difficult mask ventilation, difficult intubation or both. Soft tissue neck X-rays (anteroposterior and lateral views) and computed tomography (CT) scan are the conventional imaging tools used for airway assessment. Although neck X-rays (anteroposterior and lateral views) provide information about narrowing and displacement of trachea, they do not provide exact tracheal dimensions. While the CT scan does provide exact tracheal measurements, it has the drawback of providing only static information. The exact distensibility or direction of manipulation that leads to 'widening or opening up of the trachea' is not assessed. Ultrasound of the airway not only helps to localise tracheal narrowing but also ascertains the size of narrowing. It also gives information of change in tracheal diameter (improvement or worsening) on displacement of the thyroid swelling.
In the present case, after studying the X-rays of the soft tissues of the neck, the anaesthesiologist would have logically thought that a rightward displacement of the thyroid swelling would improve the tracheal diameter. On the contrary, rightward displacement of the swelling reduced the tracheal diameter, while a significant improvement in diameter of the trachea resulted in displacing the swelling towards the left. This dynamic evaluation helped us to choose the appropriate size of flexometallic tube to be used. It also guided the direction of manipulation required intraoperatively. Ultrasound examination helps one in knowing whether the trachea is distensible or not. Being a dynamic assessment, it also provides the operator information regarding which direction the swelling should be manoeuvred and how much such manoeuvring is helpful in opening up the airway. Asymmetrical thyroid swelling over the neck causes variable deformity of the trachea, presenting as compression or deviation at different levels. Because of the asymmetrical growth of the thyroid gland, manipulation from one direction may produce a countertraction on the other side producing a new temporary deformity of the trachea. We believe that this may be the cause of many failed intubations in patients with thyroid swelling compressing the trachea. This finding has not been documented well in literature due to the nonavailability of feasible imaging techniques. We believe that point-of-care ultrasound can be used to calculate baseline tracheal dimensions. It could also be used to assess the effect of thyroid manipulation on tracheal dimensions. These measurements can help in selecting the size and type of endotracheal tube. The backup plan in dealing with a difficult airway included reverting to mask ventilation, choosing a smaller size flexometallic or polyvinylchloride tube and waking up the patient from general anaesthesia.
Conventional parameters may not be true in all cases such as in ours. Dynamic assessment may help the anaesthesiologist in deciding airway management in such cases. We emphasise that static and dynamic assessments of the airway by means of radiological airway imaging and ultrasonography respectively are vital in planning an appropriate airway management strategy. However, the clinical scenario should be meticulously judged in planning the airway in individual cases.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given her consent for her images and other clinical information to be reported in the journal. The patient understands that her name and initials will not be published and due efforts will be made to conceal her identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
| References|| |
Tripathy DK, Ravishankar M. Airway management in a case of severe tracheal narrowing by retrosternal goiter - A case report. Internet J Anesthesiol 2010;23:2.
Gupta B, Gupta L. Significance of the outer diameter of an endotracheal tube: A lesser-known parameter. Korean J Anesthesiol 2019;72:72-3.
Sivakumar RK, Mohan VK, Venkatachalapathy R, Kundra P. Ultrasonography as a novel airway assessment tool for preoperative dynamic airway evaluation in an anticipated difficult airway. Indian J Anaesth 2017;61:1023-5.
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