+ When the main stage of the operation was finished, and the tracheal anastomosis was formed, the catheter was removed. The 8 endotracheal tube on the vocal cords was inserted, the patient was switched to convective CMV Group 2: Apneic intermittent ventilation (AIV) + When the surgeon cut the trachea, the central endotracheal tube was pulled up on the vocal cords to wait.