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Awake intubation using Pentax AWS video-laryngoscope after failed fibreoptic intubation in a morbidly obese patient with a massive thyroid tumour and tracheal compression.

A morbidly obese 53-year-old male, weighing 134 kg with a body mass index of 45.3, was scheduled for total thyroidectomy. He presented with a massive multi-nodular goitre with pressure symptoms which included difficulty breathing and hoarseness of voice. His past medical history included severe obstructive sleep apnoea on home continuous positive airway pressure therapy, ischemic heart disease, chronic obstructive airway disease, type II diabetes mellitus and hypertension. Computed tomography of his neck demonstrated a gross enlargement of the thyroid gland with the right and left lobes measuring 11x6x5 cm and 10x6x7 cm respectively. This was associated with displacement of the trachea to the right and narrowing of the airway to a minimum transverse diameter of 7.7 mm. (Figure 1) Preoperative nasal endoscopy showed that the upper airway was very narrow, roughly 2 mm at the glottis.

Difficult intubation was acknowledged and anticipated. Multiple attempts of awake intubation with 11 Fr fibreoptic bronchoscope failed both orally and nasally by two experienced specialist anaesthetists. The surgery was cancelled for that day and the patient was re-scheduled two days later. This time an awake intubation by Pentax AWS-S100 video-laryngoscope (Pentax Corporation, Tokyo, Japan) was planned. Our alternative plan if this failed was to induce the patient with intravenous propofol and perform direct laryngoscopy, with ENT surgeons and rigid bronchoscope readily available.

After adequate topicalisation, the patient's anxiety and gag reflex were further reduced by a low dose remifentanil target-controlled infusion up to 1 ng/ml. Visualising the glottis was possible with a Cormack Lehane glottic view grade 2 using the Pentax AWS video-laryngoscope, however the glottis appeared very narrow with significant surrounding oedema and mucosal hypertrophy. An initial attempt to pass the armoured endotracheal tube failed due to the narrow glottis. Subsequently, a Frova (Cook Medical, Bjaeverskov, Denmark) airway intubation catheter was inserted under video assistance and the tube was successfully advanced into the trachea. Anaesthesia was safely induced intravenously after the airway was secured.

Massive thyroid tumours are a potential cause of difficult airway. In our case the location and size of the tumour and co-existing morbid obesity and obstructive sleep apnoea posed a high risk of complete upper airway obstruction, if anaesthesia was induced and muscle relaxation administered before intubation. If a 'can't ventilate, can't intubate' situation had occurred, it was judged that it would be impossible to perform an emergency surgical airway. Hence, in adherence to the difficult airway algorithm of American Society of Anesthesiologists, awake fibreoptic intubation in the sitting position was considered as the first and the safest option.

[FIGURE 1 OMITTED]

It is uncommon to have a failed fibreoptic intubation. Ovassapian et al have reported a failure rate of 1.2% in their clinical practice (1). We believe the main reason for the failed fibreoptic intubation in our patient was the narrow compressed airway along with extensive mucosal hypertrophy. It was impossible to advance the bronchoscope, as this had possibly plugged the pathway and precipitated a severe form of airway obstruction. Our patient experienced difficulty breathing and choking sensation when the bronchoscope was advanced and became uncooperative. This was overcome by the usage of Pentax AWS guided insertion of Frova airway intubation catheter, which is commonly called Cook's single-use bougie (2) and the tracheal tube was advanced over it.

Awake video-laryngoscopies including the Pentax-AWS have been used in patients with unstable necks, difficult airway, severe ankylosing spondylitis and morbid obesity (3,4). There were two recent reports of successful intubation by video-laryngoscopes for failed fibreoptic intubation (5,6).

Our situation is different in that, in all previous cases excluding the failed fibreoptic cases, alternative modes of securing the airway including awake fibreoptic intubation would be possible, if video-laryngoscopy had failed. In the failed fibreoptic intubation cases reported recently, the patients were anaesthetised before securing the airway with the video-laryngoscope. If there are no concerns about inducing anaesthesia before securing the airway, there could be a range of other alternative methods including LMA as a conduit for fibreoptic intubation and the intubating laryngeal mask airway. In our patient it was impossible to perform awake fibreoptic intubation and awake video-laryngoscopy by the Pentax AWS was life-saving. A Frova airway intubation catheter may be of benefit in this particular situation. The possibility of the patient self-ventilating through the catheter may avoid a severe form of airway obstruction.

We believe this is a unique clinical situation where definite guidelines and recommendations are lacking. Acquiring expertise in video-laryngoscope guided techniques might be useful and potentially life-saving, in certain specific scenarios in the difficult airway management. The position of awake intubation in difficult airway algorithms and guidelines should be explored further to include the role of this non-invasive technique of video-laryngoscope aided intubation, especially when awake fibreoptic intubation fails.

J. JEYADOSS

N. NANJAPPA

D. NEMETH

Adelaide, South Australia

References

(1.) Ovassapian A, Yelich SJ, Dykes MH, Brunner EE. Fiberoptic nasotracheal intubation--incidence and causes of failure. Anesth Analg 1983; 62:692-695.

(2.) Dravid RM, Chekairi A, Al-Shaikh S. Airway management during microlaryngoscopic surgery with a Frova airway intubation catheter. J Clin Anesth 2006; 18:460-462.

(3.) Asai T. Pentax-AWS videolaryngoscope for awake nasal intubation in patients with unstable necks. Br J Anaesth 2010; 104:108-111.

(4.) Uslu B, Damgaard Nielsen R, Kristensen BB. McGrath videolaryngoscope for awake tracheal intubation in a patient with severe ankylosing spondylitis Br J Anaesth 2010; 104:118-119.

(5.) Sukhupragarn W, Churnchongkolkul W. Glidescope intubation after failed fiberoptic intubation. Paediatr Anaesth. 2010; 20:901-902.

(6.) Asai T, Ito I, Kuremoto Y, Kawashima A. [Tracheal intubation with Pentax AWS Airway Scope after failed fiberoptic intubation and failed insertion of the intubating laryngeal mask airway]. Masui 2010; 59:470-472.
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Title Annotation:Correspondence
Author:Jeyadoss, J.; Nanjappa, N.; Nemeth, D.
Publication:Anaesthesia and Intensive Care
Geographic Code:8AUST
Date:Mar 1, 2011
Words:939
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