Left mainstem bronchial intubation at an extremely short incisor-to-carina distance in a patient with severe ascites.

Unintentional left mainstem bronchial intubation after direct laryngoscopy is less common than unintentional right mainstem bronchial intubation, having only been referenced 3 times outside of the anesthesia literature. We report a case of unintentional left mainstem intubation at an extremely short incisor-to-carina distance. We hypothesize that the left mainstem intubation occurred because of a distortion of the anatomy of the tracheal bifurcation, caused by the patient's severe ascites, hepatomegaly, and collapsed right lower lobe, thus creating a shallower angle of the left mainstem bronchus from midline. The short incisor-to-carina distance can be explained by ascites-induced cephalad shift of the mediastinum.