The patient was a 60-year-old worker with repeated cough and dyspnea for ~10 years. The patient had a smoking history of 20 pack-years for 30 years and had chronic obstructive pulmonary disease and pulmonary bullae. Usually, these symptoms can be controlled using bronchodilators and inhaled corticosteroids; however, the dyspnea, cough, and sputum expectoration of the patient gradually worsened. The patient was admitted to our hospital for the first time due to sudden shortness of breath 1.5 years ago. Physical examination showed that the patient was thin, had clubbing digits, a slightly collapsed bridge of the nose, and had stunted auricles (Figures 1A-C). The chest was in a typical barrel shape, the intercostal space was widened, the breath sounds were lower, and wet rales can be heard in both lower lungs. Chest computed tomography (CT) showed reduced tracheal lumen, thickened tracheal wall, emphysema, and bilateral lung infections (Figures 2A-C). Pulmonary function tests revealed severe mixed ventilatory dysfunction, which was mainly obstructive, with a slight decrease in diffusion function (Figure 2H). Blood gas analysis suggested type 2 respiratory failure. Routine blood tests showed that white blood cells, neutrophils, and C-reactive protein were significantly elevated, suggesting an infection in the lungs. Although low-flow oxygen (2 L/min), antibiotics, glucocorticoids, and bronchodilators were administered, the patient's symptoms were not significantly relieved. A chest CT scan including the inspiratory and expiratory phases showed that the lumen of the trachea and main bronchus severely collapsed at the end of expiration compared with inspiration (Figures 2D-G). Subsequently, bronchoscopy showed that the mucosa of the trachea and main bronchi were severely hyperemic and swollen, and the cartilage had disappeared (Figures 3A-G). Although the lumen was normal during inhalation, the tracheal membrane protruded into the lumen during exhalation, resulting in the complete collapse of the lumen, and inability to eliminate secretions; these changes were not seen in the distal airway. A diagnosis of RP with TBM was highly suspected. Subsequently, a biopsy of the patient's auricular cartilage was performed. Pathology reports showed multiple necrotic chondrocytes accompanied by inflammatory cell infiltration (Figure 1D). Finally, the diagnosis was clear and consistent with our hypothesis. Subsequently, three nickel-titanium alloy coated memory stents were implanted in the trachea and bilateral main bronchus under local anesthesia (Figures 2I-K). Pulmonary function tests revealed moderate mixed ventilatory dysfunction, which was mainly obstructive, with a slight decrease in diffusion function (Figure 2L). Prednisone (1 mg/kg) was continued, and the patient was discharged. The patient was readmitted to our hospital for worsening dyspnea 1 year ago. Chest CT showed an unobstructed trachea and bilateral main bronchus, the stent was well-fixed, and the subglottis and upper part of the stent were slightly narrowed (Figures 2M-Q). Bronchoscopy showed that the lumen of the subglottis to the upper segment of the tracheal stent was narrow, the mucosa was severely swollen, cartilage had disappeared, and granulation hyperplasia was present (Figures 3H-L). The narrow lesion was significantly improved after bronchoscopy-guided argon plasma coagulation, and CO2 cryoablation was performed, which significantly relieved the patient's symptoms (Figures 3M-P). The patient was administered prednisone (1 mg/kg). Six months ago, the patient was readmitted to our hospital because of sudden dyspnea. Emergency chest CT and bronchoscopy showed granulation hyperplasia and scar tissue in the lumen of the subglottis to the upper segment of the tracheal stent, hyperemia and swelling of the mucosa, and a large amount of thick sputum blockage in the lumen, resulting in severe narrowing of the lumen (Figures 2R, 3Q). To avoid the risk of major airway bleeding and asphyxia during bronchoscopy under conventional ventilation, we decided to perform bronchoscopy-guided interventional therapy with VV-ECMO using a heparin-coated membrane lung.
We first percutaneously inserted a 22-Fr cannula into the left femoral vein and a 16-Fr venous cannula into the right internal jugular vein of the patient. The direction of the pipe connection was as follows: left femoral vein   centrifugal pump   membrane lung   right internal jugular vein. The circulatory system was pre-filled with Wanwen 1,500 mL and continuously infused with heparin during ECMO. The mean arterial pressure, SpO2, hematocrit, and activated clotting time (ACT) during transfusion were monitored. The ECMO speed was 3,500 rpm, the blood flow velocity was 3 L/min, the average arterial pressure was maintained at 90 +- 10 mmHg, and ACT was maintained at 250 s. We performed bronchoscopy interventional therapy under general anesthesia with oxygen supply guaranteed by ECMO. For the intervention, we first used a CO2 cryotherapy instrument to remove the local granulation tissue during the operation and then a needle-shaped high-frequency electrosurgical knife to make a radial cut on the narrow opening (Figure 3R). Subsequently, balloon dilations were performed three times at the lesion. Finally, CO2 cryoablation was performed (Figure 3S). The total treatment time was 1 h, the intraoperative bleeding volume was ~50 mL, and the SPO2 was maintained at 90-95%; the rest of the vital signs were stable. After the operation, the patient's tracheal stenosis significantly improved, and the bronchoscope was able to enter the distal airway smoothly, enabling the aspiration of large amounts of viscous secretions; the airway stent was in a good position and no serious complications, such as rupture were observed (Figures 3T-X, 2S,T). After the operation, the patient was transferred to the ICU for monitoring. After 12 h, ECMO support was stopped, and the patient was implanted with a laryngeal mask and switched to a mechanical ventilator for oxygenation. On the second day after surgery, we removed the laryngeal mask and switched to non-invasive ventilator-assisted ventilation. On the fourth day, the patient was discharged from the hospital. However, the patient eventually died due to sudden respiratory failure during half year follow-up. Clinical history of the patient can be seen in Figure 4.