Anaesthesia management for subtotal thyroidectomy in a case of multinodular goitre with retrosternal extension and superior vena caval syndrome.

ST Dave, SK Kamath, AN Shetty, LD Naik 
 

Correspondence Address:
S T Dave

Full Text

Sir,

A 55-year-old female (65 kg) with multinodular goitre with retrosternal extension and superior venacaval syndrome was posted for subtotal thyroidectomy. Computerised tomographic (CT) scan showed the retrosternal extension of goitre, terminating 20 mm cephalad to the main pulmonary trunk, which displaced the thymus caudally and major branches of aorta posteriorly. The trachea was compressed in the sagittal plane more severely in the suprasternal region.

An awake intubation was planned. A direct laryngoscopy done a day prior revealed trachea shifted to extreme right and cord movements to be normal.

Right femoral vein cannulation was done in view of superior vena caval syndrome. Patient was premedicated with 0.2 mg glycopyrrolate. Oral cavity was anaesthetised using 2% viscous lignocaine gargles, followed by application of 2% lignocaine jelly to lips, tongue and posterior pharynx.

In supine position with a 20 degrees head high, after preoxygenating, the cords were sprayed with 4 puffs of 10% topical lignocaine. Laryngoscopy was done and patient was intubated with 28 No. cuffed armored tube. The patient was anaesthetised using intravenous 2.5% thiopentone sodium and vecuronium bromide. Intravenous midazolam 2 mg and pentazocine 30 mg were given for sedation. Shoulder bolster of appropriate size was placed and maximum extension possible at the atlantooccipital joint was given. Head high of 30 degrees and foot high of 30 degrees were given. Anaesthesia was maintained with oxygen, nitrous oxide in the ratio of 40:60 and vecuronium bromide. Subtotal thyroidectomy was performed with enucleation of the retrosternal extension. As tracheomalacia was suspected, tracheostomy was performed with a 7 number portex cuff tube at the level of 3rd tracheal cartilage.

At the end of the surgery there was a sudden difficulty in ventilating the patient as the tracheostomy tube had slipped off. A direct laryngoscopy was performed (in view of excessive oozing at the surgical site) and a 6 number cuffed endotracheal tube was passed beyond the tracheostomy incision and cuff inflated and ventilation continued through endotracheal tube. The tracheostomy tube was reinserted later.

After reversal of neuromuscular blockade, a direct laryngoscopy was performed which showed normal cord movements. Intraoperative blood loss was 500cc. Two litres of crystalloids were infused.

In patients with retrosternal goitre with superior vena caval syndrome, anaesthesia can result in loss of muscle tone that can lead to complete obstruction of the airway. The prime objective in the management of retrosternal goitre is to bypass the obstruction and gain access to the airway in an awake state.

Preoperative direct laryngoscopy helps to visualise the cords and epiglottis and to plan the protocol for awake intubation. If tracheal compression is suspected it should be evaluated by CT.[1]

Premedication with antisialogue given half an hour prior, gives optimum effect for topical oral anaesthesia to act. Sedatives and analgesics must be withheld in view of anticipated difficult intubation. Posterior pharynx has to be well anaesthetised to prevent bucking.

Preoxygenation creates an oxygen reserve in the patients’ functional residual capacity that may be extremely important in case of an anticipated difficult intubation.[2]

Long armored tube should be used to bypass the tracheal constriction (29 cm) Laryngoscope should not be removed until the patient is anaesthetised and the tube secured in place to prevent accidental extubation. When tracheomalacia is suspected a prophylactic tracheostomy should be done.

An intravenous line in the upper extremity is contraindicated in view of severe venous hypertension and long and unpredictable circulation time that result from superior vena caval obstruction.[1]

During ventilation there should be a sufficient pause between expiration and inspiration to enable adequate venous return. The inflation pressure required to ventilate the lungs should be kept to a minimum to prevent further decrease in venous return.

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