Asphyxia after thyroid surgery is usually associated with the following factors: severe oedema of the larynx due to irritation from surgery or tracheal intubation, which affects the flow of air in and out of the airway; asphyxia due to post-operative haemorrhage and compression of the thyroid gland, mostly in more obese patients with a short thick neck; asphyxia after thyroidectomy due to collapse of the trachea with softening and difficulty in breathing; and damage to the laryngeal recurrent nerve.