The most dangerous complication after thyroid surgery is dyspnea and asphyxia. The causes of dyspnea after thyroid surgery mainly include two kinds: 1. Because the blood and exudate from the local surgical incision accumulates in the surgical field and cannot be drained out through the drainage tube, it will certainly compress the trachea, thus leading to dyspnea and asphyxia; 2. Mainly because the thyroid tumor is too large or the long-term compression causes the trachea to soften. Because the softened trachea may collapse leading to difficulty in breathing, thus causing asphyxia. Once the patient suffocates, death is bound to occur.