The most dangerous complication after thyroid surgery is dyspnea and asphyxia. The causes of dyspnea after thyroid surgery include two main reasons: 1, because the blood and fluid from the local surgical incision accumulates in the surgical field, which can not be induced through the drainage tube, and inevitably presses on the trachea, which leads to respiratory difficulties and asphyxia; 2, mainly because the thyroid tumor is too large or long-term pressure leads to the softening of the trachea, after surgery Because the softened trachea may have tracheal collapse leading to dyspnea, thus causing asphyxia. Once the patient suffocates, death is bound to occur.