AIMS: The variations in upper esophageal anatomy currently are unknown. This study was carried out to evaluate this variation and assess its impact on transesophageal echocardiography probe insertion.

METHODS: We included 9 consecutive cadavers studied at the University of Maryland School of Medicine's Clinical Surgical Laboratory. Each cadaver was first intubated blindly by an echocardiographer (KAA) and then under direct vision with a UE Medical VL 400 video laryngoscope (Newton, MA) by an anesthesiologist (JD).

RESULTS: The visually guided method took a shorter average time (19.4 ± 13.4 seconds) and fewer passes (2.4 ± 2.1 passes) than blind insertion (30.3 ± 19.1 seconds, 5.3 ± 3.3 passes). None of the cadavers had the esophagus located directly posterior to the trachea. The esophageal hiatus was posterior and to the right of the trachea in most (n = 6); in these, the traditional "forward" jaw thrust helped to open the esophageal hiatus. Two cadavers had the esophagus and trachea located almost side by side, and in these the "forward" jaw thrust method failed. Instead, the jaw needed to be pulled to the left in order to advance the probe.

CONCLUSION: This is the first study to describe anatomic variations in the location of and relationship between the upper esophageal sphincter and the larynx for the purpose of transesophageal echocardiography probe insertion. Awareness of the side-by-side anatomic variation can help to improve esophageal intubation by prompting the use of a new "pull to the side" technique instead of the traditional "forward" jaw thrust.