While cardiac surgery is and has been the dominant clinical area of use for intraoperative transesophageal echocardiography (TEE), initial studies did not specifically focus on this field of expertise. The new technology was expected to offer incremental value in noncardiac surgery as a tool to detect intracardiac emboli, for example, during craniotomies in sitting position and orthopedic surgery,1–4 as a noninvasive and continuous hemodynamic monitor during major surgical procedures5,6 and as a sensitive instrument to diagnose myocardial ischemia in high-risk patients.7,8 While subsequent studies confirmed the utility of TEE for such indications, the enthusiasm and adoption of TEE in noncardiac surgery remained modest and mainly confined to the practice of pioneers in the field. Reasons for this slow acceptance included a limited access to (heavy and expensive) echo equipment, a shortage of experienced echo trainers in anesthesia, and, most importantly, a lack of prospective outcome studies supporting the routine use of perioperative TEE outside the cardiac surgical setting.
In a collaborative effort, the American Society of Echocardiography (ASE) and the Society of Cardiovascular Anesthesiologists (SCA) published a consensus document that emphasized the significant role of a “basic” perioperative TEE in the care and treatment of an unstable surgical patient and clarified its scope as an “intraoperative monitoring technique, focusing on cardiac causes of hemodynamic or ventilatory instability, including ventricular size and function, valvular anatomy and function, volume status, pericardial abnormalities and complications from invasive procedures, as well as the clinical impact or etiology of pulmonary dysfunction.”9 As it is impossible to cover all possible scenarios where intraoperative TEE is expected to or has shown its value, the following chapter follows a more pragmatic approach in using specific surgical settings to illustrate the most prevalent and clinically important applications. Specific attention is dedicated to liver transplantation as a prototype procedure for which the broad potential of intraprocedural TEE monitoring can be exploited to its fullest extent.
VASCULAR AND ABDOMINAL SURGERY
Patients undergoing vascular surgery are at increased risk (5% to 25%) for perioperative cardiac complications such as unstable angina, congestive heart failure, myocardial infarction, and cardiac death. The strong association between ischemic heart disease and peripheral arterial disease justify the use of advanced techniques to detect myocardial ischemic events in vascular surgery. The diagnosis of cardiac ischemia with TEE is based on the detection of regional heterogeneity in the timing and extent of wall thickening during systole. A semiquantitative scale is used to describe the severity of segmental wall motion abnormality (SWMA), while the exact location is indicated on a 17-segment model of the left ventricle (LV).10 The distribution and extent of SWMA correspond to the perfusion territory of the three major coronary arteries.
SWMAs have been reported to occur within 15 seconds of coronary occlusion, whereas ST-segment elevations are seen after only 30 to 60 seconds. ...