Incidental left main bronchus obstruction during left-sided double-lumen tube intubation of a patient with an unrecognized tracheal bronchus

INTRODUCTION Tracheal bronchus is a right-sided anomalous bronchus arising from the trachea above the main carina and occurs in 0.1% to 2% of the general population. CASE PRESENTATION We present a case of left main bronchus obstruction during a left-sided double-lumen tube intubation in a patient with an unrecognized tracheal bronchus. After the intubation, to confirm the position of the tube, we observed what we believed was the carina with a fiberoptic bronchoscope, but it was a site between the tracheal bronchus and the right main bronchus. Thus, a right-sided intubation was performed, and the left main bronchus was obstructed with a bronchial cuff. As a result of the inappropriate ventilation, peak inspiratory pressure was elevated and arterial oxygen saturation decreased. CONCLUSION Anesthesiologists should keep in mind the possibility of anatomical variation in the large airways, and bronchoscopy should be accompanied by cautious auscultation and confirmation of the division of the bronchus.