Benzocaine induced methemoglobinemia: a potentially fatal complication of transesophageal echocardiography.

Transesophageal echocardiography (TEE) is a relatively safe procedure with complications including bleeding, esophageal perforation, and respiratory failure being rare. One of our patients recently developed severe cyanosis despite pulse oximetry of 85% following TEE. This directs our attention to a rare, easily treatable, but potentially fatal complication of this procedure.