Transesophageal echocardiography: what the anesthesiologist has to know.

Transesophageal echocardiography (TEE) is a very powerful intraoperative monitoring tool. It allows precise assessment of cardiac anatomy together with dynamic quantification of myocardial performance and flows through the heart chambers. With a high safety profile TEE counts few absolute contraindications. Performance of TEE requires dedicated training. Certification pathways are offered in Europe and North America. Focused, basic and advanced scanning protocols have been lately described for intraoperative and emergent use. Many specific TEE applications have been described in non-cardiac surgery most of which only supported by a limited number of studies. Advanced TEE allows quantitative assessment of left and right ventricular function but its application has not become standard of care outside the cardiac operative room partially due to lack of scientific evidence. TEE can provide quantification of left ad right ventricular cardiac output and diastolic function. It may also identify fluid responsiveness. TEE is more sensitive than ECG in identifying myocardial ischemia but it requires advanced training. Basic TEE can identify common causes of hemodynamic instability such as hypovolemia, pulmonary embolism and tamponade. Unexplained hemodynamic instability is the only strong indication in non-cardiac surgery. Qualitative assessment based on a simplified protocol seams to adequately address the clinical needs in this specific scenario. More studies are required to support the use of TEE outside of cardiac surgery at its full potential.