Pulmonary Perfusion Using Intrabronchial Capnography in Pulmonary Artery Stenosis.

Stenting at the flow-limiting segment can improve the ventilation-perfusion ratio in patients with central airway stenosis. However, there is no quantitative examination for assessing the perfusion status during interventional bronchoscopy. Intrabronchial capnography can estimate regional gas exchange by measuring carbon dioxide concentration. We herein report a case of bilateral bronchial stenosis where stenting was able to improve ventilation-perfusion ratio using intrabronchial capnography. A 44-year-old man was admitted to our institution with orthopnea. Chest computed tomography showed an extrinsic compression at the bilateral main bronchus and right pulmonary artery due to a mediastinal mass. After introduction of general anesthesia, arterial oxygen tension suddenly decreased in the supine position. After initial stenting, an increase was seen in ventilation at the right lung; however, a ventilation-perfusion mismatch occurred due to an increase in dead-space ventilation at the right pulmonary artery stenosis. Intrabronchial capnography was an effective modality to confirm the regional perfusion status during interventional bronchoscopy in real time.