Contraindications to bronchoscopy: 1, poor general condition, weakness can not tolerate bronchoscopy. 2, there are mental abnormalities, can not cooperate with the examination. 3, have chronic cardiovascular disease, such as unstable angina, myocardial infarction, severe arrhythmia, severe cardiac insufficiency, hypertension, blood pressure before examination is still higher than 160/100mmhg, aneurysm; recent cerebrovascular accident patients. 4, have chronic respiratory disease with severe respiratory insufficiency, if the examination is required, it can be performed under oxygen supply and mechanical ventilation. 5.Anesthetic drug allergy, can not be replaced by other drugs. 6.People with severe bleeding tendency and coagulation mechanism disorder. 7, the respiratory tract has acute purulent inflammation with hyperthermia, acute asthma attack and is hemoptysis, can be performed after the remission of the disease. 8.The airway has deformities and the bronchoscope cannot be inserted. 9.Large amount of active bleeding in the airway, beyond the removal ability of the bronchoscope. The above contraindications are all relative contraindications, if the patient’s condition is stable after active treatment, or if the condition has changed neither is a contraindication to hinder the examination. If the patient is allergic to this type of anesthetic, if a replacement non-allergic anesthetic is found, it can be done; and if the patient has heart failure, after treatment, heart function will be improved, you can also do the relevant examination.