Background. In severe airway obstruction, patients complain of dyspnea due to flow limitation, and respiratory failure can occur due to ventilation-perfusion mismatch. We previously reported the significance of estimating the regional pulmonary function during interventional bronchoscopy. The multiple pulmonary function measurement system (FB-8010^®) has been certified in Japan since January 2020. Purpose. To assess the flow limitation and ventilation-perfusion mismatch in patients with airway obstruction using the multiple pulmonary function measurement system during bronchoscopy. Methods. Lateral airway pressure was measured simultaneously at two points using a double-lumen catheter and the pressure difference between two points was calculated. Lateral airway pressure was plotted on the x/y axes, representing the pressure-pressure curve (P-P curve). We then calculated the angle of the P-P curve defined as the angle between the peak inspiratory and expiratory pressure points and baseline of the angle. In addition, partial pressure of oxygen (PO₂) and partial pressure of carbon dioxide (PCO₂) were measured at the target region using a single-lumen catheter. Results. Pressure differences were noted at the site of airway obstruction, and the angle of the P-P curve was small. When flow limitation was restored after stenting, the pressure differences disappeared, and the angle of the P-P curve was closer to 45°. The baseline PO₂ was lower for the severe bronchial obstruction side than the healthy side, and there was no marked difference in PCO₂. After the airway was restored, the difference between the right and left was reduced in the baseline PO₂. Conclusion. This novel multiple pulmonary function measurement system was able to assess the regional pulmonary function during bronchoscopy. The lateral airway pressure, PO₂ and PCO₂ help clarify the pathophysiology and estimate the outcome of interventional procedures in real-time.

Background. The safety of an endobronchial ultrasound-guided transbronchial biopsy with a guide sheath (EBUS-GS-TBB), endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA), a transbronchial lung biopsy (TBLB), and an endobronchial biopsy (EBB) has not been established in patients receiving antiplatelet drugs and anticoagulants. We therefore compared adverse event rates between patients with and without antiplatelet drugs and anticoagulants when these drugs were interrupted before the biopsy. Methods. We retrospectively analyzed cases of EBUS-GS-TBB, EBUS-TBNA, TBLB, and EBB performed at the Hokkaido University Hospital from August 2010 to July 2015. Univariate and multivariate analyses were performed to examine the association between adverse events and antithrombotic drugs, age, gender, and other factors. Antiplatelet drugs and anticoagulants were interrupted according to the Japan Society for Respiratory Endoscopy's manual (Ver. 2.0 or Ver. 3.0). Results. A transbronchial biopsy was performed in 1320 cases. The number of biopsies performed in patients without antithrombotic drugs, with only antiplatelet drugs, with only anticoagulants, and with both were 1145, 131, 24, and 20, respectively. The adverse event rates were 7.0% for all patients, 7.2% without antithrombotic drugs, 4.6% with antiplatelet drugs only, 0.0% with anticoagulants only, and 15.0% with both. There was no significant difference in adverse event rates between patients without antithrombotic drugs and those with antithrombotic drugs and anticoagulants in both univariate and multivariate analyses (antiplatelet drugs only: p=0.463; anticoagulants only: p=0.988; both: p=0.249 in the multivariate analysis). Conclusion. A transbronchial biopsy was able to be performed in patients taking antiplatelet drugs and anticoagulants without significantly increasing adverse events by providing an appropriate withdrawal period.

A 22-year-old asymptomatic woman was referred to our hospital after chest radiography showed a mass shadow in the right upper lung field. Computed tomography showed a 3-cm mass shadow in the upper lobe of the right lung. Initially, malignancy was suspected, but a thorough examination of reconstructed images, ventilation/perfusion scintigraphy, and bronchoscopy showed congenital bronchial atresia. She has been followed up without any interventions for nine years, with no serious complications. There are no clear guidelines for diagnosing or treating asymptomatic bronchial atresia, including indications for surgery, which are controversial.

Background. Carotid body tumor (CBT) is a rare tumor that is histopathologically a paraganglioma (PGL). Due to the nature of the hypervascular tumor, a biopsy for such tumors, including the primary lesion, is often difficult. Case. A 65-year-old woman who had undergone multiple surgeries for right CBT approximately 13 years earlier developed hemosputum during follow-up after surgery for breast cancer. She was referred to our department because contrast-enhanced computed tomography (CT) showed a nodule in the left lower lung lobe with severe protrusion into the B⁶ bronchus. CT also showed multiple pulmonary nodules in both lungs and multiple osteoblastic lesions. Fluorodeoxyglucose-positron emission tomography (FDG-PET) -CT showed an uptake of FDG in these lesions. Bronchoscopy revealed a reddish polypoid lesion protruding into the orifice of the B⁶ bronchus, with stenosis of B⁶. Since bleeding from the tumor was observed on contact with the bronchoscope and biopsy forceps, the biopsy under local anesthesia was abandoned. A bronchoscopic biopsy was subsequently performed under general anesthesia and tracheal intubation, and bleeding was easily controlled using a laser. Histologically, the biopsy specimen revealed PGL, based on which we diagnosed multiple pulmonary metastases and bone metastases of CBT. Radiotherapy was performed for the lung tumor at S⁶ to control airway bleeding, which resulted in shrinkage of the tumor and disappearance of the hemosputum. Conclusion. A bronchoscopic biopsy can be safely performed under general anesthesia with positive pressure ventilation for pulmonary metastasis of CBTs, allowing for a definitive histological diagnosis.

Background. Recently, the number of cases of dental airway foreign bodies in the elderly has been increasing. Cases.Case 1: An 80-year-old man aspirated a metal core during dental treatment. We were able to successfully remove it with flexible bronchofiberscopy using biopsy forceps. Case 2: A 79-year-old man was hospitalized for cerebral infarction. During hospitalization, he developed aspiration pneumonia, and we incidentally identified a fused tooth on an imaging examination. We removed it with an endoscope using a gastrointestinal endoscope and large biopsy forceps. Case 3: A 76-year-old man developed a cough after dental treatment, and we found a foreign body on an imaging examination. A dental crown was identified, and the flat portion of it was grasped with W-shaped forceps in the short-axis direction and extracted. Conclusion. We recommend imaging examinations if dental airway foreign bodies are suspected, as they have few clinical symptoms, especially in the elderly. It is necessary to understand the location and shape of the foreign body and to then use an appropriate device after preparing many devices. Weakly fixed teeth, dentures, or crowns that may become spontaneously dislodged should be treated as soon as possible.

Background. Methotrexate (MTX) is commonly prescribed in the treatment of rheumatoid arthritis leading to long-term usage, which then may be associated with a variety of pulmonary lesions. This is a case report of a woman with a 23-year history of taking MTX. Case presentation. A 65-year-old woman had a history of rheumatoid arthritis that had been diagnosed at age 26 years old. She had began treatment with MTX at age 43 years old. She presented to our hospital with a 7-day history of a fever and cough, and initial chest radiography showed multiple nodular shadows of unequal size in the right middle and lower lung fields. Subsequent computed tomography of the chest detected multiple nodular lesions in both lungs and enlarged lymph nodes in the left submandibular, upper mediastinum, and subtracheal bifurcation. Blood tests showed elevated levels of C-reactive protein and soluble interleukin-2 receptor as well as decreased lymphocyte counts. Bronchoscopy revealed a white, irregular, raised lesion in the trachea at the tracheal bifurcation. A direct visual bronchoscopic biopsy of this lesion and a percutaneous biopsy of the enlarged left submandibular lymph node revealed the dense proliferation of small to medium-sized lymphocytes, suggestive of other iatrogenic immunodeficiency-associated lymphoproliferative disorders (OIIA-LPD) (MTX-associated lymphoproliferative disorders) of T-cell origin. Conclusion. An endobronchial biopsy was useful for diagnosing of OIIA-LPD induced by MTX. Bronchoscopy should be performed when pulmonary involvement is suspected on radiographic imaging, and direct visual biopsy should be performed when airway involvement is detected on bronchoscopy.

Case report. A 49-year-old man with a diagnosis of squamous cell carcinoma of the left upper lobe (cT4N2M0 stage IIIB) received chemoradiotherapy. The response assessment was progressive disease, resulting in complete left pulmonary atelectasis. He developed right-sided pneumothorax and received pleurodesis. However, the pulmonary air leaks continued, and he was referred to our department. Based on the degree of air leak, we considered pleurodesis not likely to be effective for the pneumothorax and decided to perform surgery instead. Computed tomography findings indicated that air leaks had occurred from one of the many bullae in the upper right lobe. To perform differential lung ventilation, a bronchial blocker was placed at the entrance of the right upper lobe bronchus, after which thoracoscopic bullectomy was performed. A clear operative field was secured, and intraoperative oxygenation did not decline. The surgery was completed safely. After surgery, the chest tube was removed, and the patient's quality of life improved. Conclusion. Surgical treatment should be considered when pleurodesis is ineffective against contralateral pneumothorax in a patient who develops tumor-induced complete unilateral atelectasis.

Background. We herein report a patient who underwent surgery for lung cancer of the right upper lobe in whom the right B³ arose from the middle lobar branch. Case Report. A 68-year-old woman was found to have a partially solid mass (maximum diameter, 47 mm; solid diameter, 42 mm) in the right upper lobe S¹b. The right B³ arose from the middle lobar bronchus. During surgery, V^1-3 were transected, after which the superior trunk of the pulmonary artery and B¹⁺² were transected. A³a and A³b were also transected, and B³ was identified and transected. Finally, a fissure was created between the upper and middle lobes. Conclusions. In cases with a bronchial anomaly, a careful preoperative evaluation based on bronchoscopic and computed tomography findings is important to ensure a safe surgery.

Background. We report a case of pulmonary sequestration and cystic bronchiectasis associated with Nocardia infection. Case. A 46-year-old man was referred for further evaluation of an infected pulmonary cyst. Nocardia was detected in a sputum sample by Gram staining, but despite treatment for 2 years, his respiratory symptoms recurred. Because the lesion was confined to the right lower lobe of the lung, we performed surgical excision. Contrast-enhanced computed tomography (CT) performed before surgery showed aberrant arteries entering the right lower lobe from the descending aorta. This finding led to the diagnosis of pulmonary sequestration complicated by Nocardia infection. After undergoing right lower lobectomy by video-assisted thoracic surgery, the respiratory symptoms improved and have not recurred in 5 years. Conclusion.Nocardia is an opportunistic pathogen. Pulmonary structural abnormalities have been reported to be risk factors for pulmonary infection; however, Nocardia infection of a pulmonary sequestration is very rare. Contrast-enhanced CT should be performed when treatment refractory Nocardia infection is localized in the mediastinal side of the lower lobe, and pulmonary sequestration cannot be ruled out.

Background. When tracheal stenosis developed in a patient who had undergone total gastrectomy for gastric cancer, the presence of inflammatory lesions with fibrosis around the trachea required the differentiation of fibrosing mediastinitis from mediastinal metastasis. Case Presentation. Five years after total gastrectomy, tracheal stenosis was observed in a 67-year-old man being followed at our institution. The previous year, computed tomography had shown an area of soft tissue density around the trachea, and the density of that soft tissue had now further increased. Fibrosing mediastinitis was suspected, so endobronchial ultrasound-guided transbronchial fine-needle aspiration (EBUS-TBNA) was performed to sample the anterior tracheal tissue. When a sufficient specimen could not be obtained, an ultrasound-guided needle biopsy with the head tilted to expose the neck was performed. That specimen revealed a fragment of cancer tissue with a ductal structure, resulting in a diagnosis of metastasis to the mediastinum, accompanied by an inflammatory fibrotic lesion. A reexamination of the specimen from the gastrectomy confirmed HER2 positivity of the gastric cancer, and treatment with trastuzumab and capecitabine was started. The tracheal stenosis subsequently improved. Conclusion. The need to differentiate mediastinal metastasis from fibrosing mediastinitis rarely occurs. It is necessary to select a biopsy method that allows for sufficient sample collection based on imaging findings.