An unusual cause of intraoperative hypoxemia.

Congenital anomalies of the tracheobronchial tree are rare occurrences; however, they can lead to pulmonary complications. A tracheal bronchus is an anatomic variant in which an ectopic bronchus originates directly from the tracheal wall above the carina. Presented is a case of intraoperative hypoxemia due to right upper lobe collapse. Despite what appeared to be proper endotracheal tube positioning, this clinical scenario was found to be the result of endotracheal tube obstruction of a tracheal bronchus supplying the right upper lobe. Fiberoptic bronchoscopy proved to be a rapid diagnostic and therapeutic tool, as the endotracheal tube was able to be visually positioned above this aberrantly located bronchus.