Fiberoptic bronchoscopy is a commonly used clinical diagnostic method for respiratory diseases, which is fast, safe and economical. The development of bronchoscopy has gone through three different stages from traditional rigid bronchoscopy, fiber bronchoscopy and modern electronic bronchoscopy, TV rigid bronchoscopy. Transbronchoscopic needle aspiration biopsy (TBNA) is more suitable for the diagnosis of necrotic or submucosal lesions with meticulous specimen collection and less bleeding; it does not need to repeat the sampling on the surface of necrotic tissues or normal mucous membranes, and it can directly penetrate into the tissues with vitality to obtain the lesion tissues outside the lumen of the trachea, thus improving the positive detection rate. Zhang Caiqing, Department of Respiratory Medicine, Thousand Buddha Mountain Hospital, Shandong Province, China 1. Technical requirements of TBNA ① Familiar with the anatomical structure of the lungs and mediastinum, with good three-dimensional imagination and localization ability. ② The operator should have specialized training in practical operation. ③ Familiar with the characteristics of various types of puncture needles. ④ Skilled in positioning methods and operation techniques. 2. Purpose and contraindications of TBNA 2.1 Purpose ① Obtain the specimen of lymph nodes outside the lumen of the airway but close to the wall of the trachea and bronchus; ② Obtain the specimen of lesions in the lumen of the trachea and bronchus; ③ Obtain the specimen of lesions in the hilar area; ④ Obtain the specimen of lesions in the bronchus of the external tumor compressed segment; ⑤ Perform the stage of lung cancer; and ⑥ Perform the drainage of mediastinal cysts or abscesses. 2.2 Contraindications ①Poor general condition, weak physique cannot tolerate TBNA examination. ② Patients who are mentally abnormal and cannot cooperate with the examination. ③ Patients with severe chronic cardiovascular disease. ④ Patients with chronic respiratory disease with severe respiratory insufficiency, if the examination is necessary, it can be performed under oxygen supply, mechanical ventilation and cardiac monitoring. ⑤ Those who are allergic to anesthesia drugs and cannot be replaced by other drugs. (6) Those with serious bleeding tendency and coagulation mechanism disorder. (7) Those with acute purulent inflammation of the respiratory tract with high fever, acute asthma attack and hemoptysis, can be performed after the condition is relieved. 3 .Common complications of TBNA ① Pneumothorax and mediastinal emphysema, the incidence is low, less than 1%. ② Bleeding phenomenon, but the amount of bleeding is usually very small and often stops by itself. Infection in the mediastinum is less likely to occur. Strict aseptic operation can mostly avoid the occurrence of infection. ④ Arrhythmia or sudden death, the incidence is relatively small, before operation, repeated questioning of medical history, electrocardiography, and prepare the relevant emergency drugs. 4. Steps of TBNA 4.1 Define the anatomical sites of tracheal and parabronchial lymph nodes 1 anterior rondylar lymph node; 2 posterior rondylar lymph node; 3 right paratracheal lymph node; 4 left paratracheal lymph node; 5 right main bronchial lymph node; 6 left main bronchial lymph node; 7 right upper hilar lymph node; 8 infratrochlear lymph node; 9 right lower hilar lymph node; 10 distal rondylar lymph node; 11 left hilar lymph node 4.2 Routine localization ① Repeatedly read the chest CT and confirm the relevant structures such as the rudiment, the bronchial crescents and the aortic arch according to the chest CT films, and use them as the reference markers for puncture. ② Calculate the distance between the lesion and the marker according to the CT layer distance, and determine the angle and depth of needle insertion according to the position of the lesion on the CT. ③ Determine the puncture point and the direction of needle insertion in the lumen of the canal according to the distance between the lesion and the marker point and the angle of needle insertion determined. 4.3 Selection of appropriate puncture needles Commonly used puncture needles include: ① N1C cytology puncture needle, N2C histology puncture needle (produced by Olympus in Japan). Among them, puncture needles below 8 mm are suitable for submucosal lesions, and puncture needles above 8 mm are suitable for extra-airway lesions. ② SW-121 needle core 13 mm, 21G cytology puncture needle (outer diameter 0.8 mm, inner diameter 0.6 mm); MW-122 needle core 15 mm, 22G cytology puncture needle (outer diameter 0.7 mm, inner diameter 0.5 mm), which is easier to penetrate the trachea wall; MW-319: 19G histology puncture needle (outer diameter 1.0 mm, inner diameter 0.8 mm), which is not easy to penetrate the trachea wall MW-319: 19G histologic needle (1.0 mm OD, 0.8 mm ID), not easy to penetrate the trachea wall. All were provided by MILL-ROSE, USA. 4.4 Puncture methods and techniques The puncture methods include jerking method, advancing method, coughing method, and metal ring close to the airway wall method. Puncture techniques: ① Repeatedly read the chest CT film before the operation to determine the puncture site. ② The puncture angle is >45 degrees. ③The puncture needle is fully inserted into the wall of the trachea or bronchus. ④The puncture needle should be inserted and removed from the lesion 8 to 10 times. ⑤ Release the negative pressure before discharging the needle. 4.5 Specimen preparation ① In order to obtain a high positive rate, at least two more satisfactory specimens should be obtained during specimen preparation; ② The specimen should be quickly fixed with anhydrous ethanol after smear; ③ The puncture tissue should be fixed with formaldehyde; the rinsing fluid should also be examined cytologically; ④ Close cooperation and communication with the relevant personnel of the Department of Pathology should be made after delivery of the test to increase the accuracy of the results. 4.6 Evaluation of puncture results TBNA results are categorized into positive, suspicious and negative forms. Positive results are correlated with factors such as the size of the lymph node, the degree of abnormal elevation in the lumen, the pathological type of the tumor and the location of the lymph node. False-positive cases are rare, and most contamination comes from secretions in the airways and from mucosa with lesions. The incidence of false negatives is relatively high: close collaboration and communication with the pathologist is required to perform repeated cytology.