Since there is a large amount of secretion in the airway, the airway can be opened after the sputum is sucked out through the suction tube to prevent respiratory difficulty. The selection of suction tube has the following requirements: 1. the material of suction tube should be less damaged to the mucous membrane and the texture should be soft to facilitate the operation. 2. the suction tube should have enough length so that the sputum can be suctioned out timely and fully, especially for the deeper airway to reach the bottom. 3. the diameter of the suction tube should not be too thick or too thin, and the suction tube with the diameter of about 1-2cm can be selected for suctioning sputum. The diameter of the suction tube should not exceed half of the diameter of the artificial airway at most.4. The material of the suction tube is harmless and non-toxic to human body, and it should be disinfected regularly, and disposable suction tubes can be used if there are conditions.