Asphyxia after thyroidectomy is a very common complication. There are three main causes: 1) acute laryngeal edema caused by surgical stimulation and anesthesia, which blocks the airway and can cause asphyxia; 2) damage to the laryngeal nerve during total thyroidectomy, which can cause hoarseness, and bilateral damage to the laryngeal nerve, which can prevent the vocal cords from moving, which can cause asphyxia; 3) internal bleeding after surgery, which is also a common complication after thyroid cancer. The neck is extremely sensitive to this kind of bleeding, and a few tens or hundreds of milliliters of blood can compress the trachea and cause asphyxia.