[Usefulness and limitations of transesophageal echocardiography in anesthetic practice].
Transesophageal echocardiography (TEE) has been used as a monitor of cardiovascular function and as a diagnostic tool in anesthetic practice. TEE is the only available monitor to detect anatomical abnormalities such as of wall motion as well as valvular abnormalities. Doppler TEE has wider diagnostic functions. TEE is a very sensitive monitor to detect myocardial ischemia by recognizing wall motion abnormalities and loss of systolic wall thickening. Preload defined by left ventricular end-diastolic volume may not correlate with left ventricular end-diastolic pressure or pulmonary capillary wedge pressure (PCWP) when left ventricular compliance changes such as after coronary artery surgery. PCWP can be misleading when transmural pressure across cardiac chambers are undetermined such as in patients with cardiac tamponade or those on high positive end-expiratory pressure. In these situations, TEE is a powerful tool to link physiologic parameters and anatomy. TEE is also a very sensitive monitor to diagnose air embolism during cardiac surgery and neurosurgery in sitting position. There are, however, several shortcomings such as its cost, "too much sensitivity", requirement of some experience, interobserver variability, and so on. The computer-assisted on-line analysis would greatly augment usefulness of TEE. When these shortcomings are overcome, TEE would be one of the most important monitors in anesthetic practice.