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The value of performing transesophageal echocardiography (TEE) in the intensive care unit (ICU) is well established. Although transthoracic echocardiography (TTE) is a useful diagnostic tool in the ICU, TEE has superior diagnostic accuracy and therapeutic impact in several clinical situations, particularly for patients in shock states.1–3 Several authors have demonstrated that TEE findings lead to major therapeutic decisions between 43% and 68% of the time.1,4–6 TEE produces good image quality due to the position of the probe proximate to the heart, allowing for the use of higher frequency ultrasound with superior resolution of cardiac structures than with TTE. Although improvements in imaging, software, and portable systems have reduced the rates of inadequate image quality seen with TTE, there remain a significant percentage of patients in the ICU whose image quality with TTE is inadequate. Many factors account for this including inadequate patient positioning, lung hyperinflation, obesity, edema, and the presence of chest devices, wounds, and dressings. TTE results in adequate image quality in approximately 55% of mechanically ventilated ICU patients, with the remaining 23% and 22% of studies being of suboptimal and poor quality, respectively.3 In addition to overcoming poor image quality of TTE, TEE is often necessary for the evaluation of specific diagnoses in the ICU such as endocarditis, identifying an embolic source, intracardiac shunt, aortic dissection, and loculated pericardial effusion. For hemodynamic assessment, TEE is the only method to assess superior vena cava (SVC) variation, a predictor of volume responsiveness.7 When compared with helical computed tomography (CT), TEE has good sensitivity and specificity for central pulmonary embolism (PE) associated with right ventricular dilatation.8,9
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Critical care TEE differs from standard cardiology TEE in several ways. Typically, TEE performed by a cardiologist is an elective procedure, which has specific indications such as the evaluation for left atrial appendage thrombus, diagnosis of congenital heart disease, identification of valvular abnormalities such as endocarditis, and assessment of prosthetic valve function. Most often, the patient is not on ventilatory support and the procedure is performed outside of the ICU. In comparison, critical care TEE emphasizes hemodynamic evaluation of cardiopulmonary failure. It is a useful diagnostic tool allowing differentiation between shock subtypes in the critically ill while replacing invasive procedures such as the insertion of a pulmonary artery catheter. Because this chapter is written for the intensivist, our emphasis will be on utilization of TEE in the critical care setting rather than focusing on a cardiology type TEE examination.
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Critical care TEE is routinely performed in large ICUs in Europe; for example, in Hospital Ambroise-Pare in Boulogne and the Erasme University Hospital in Brussels, where it is considered a routine procedure for the assessment of the shock state. In France, there is a well-defined training sequence for attendings and fellows developed by Societe de Reanimation de Langue Francaise that includes training in critical care TEE. In Australia, ...