Chapter 8

The value of performing transesophageal echocardiography (TEE) in intensive care unit (ICU) patients is well established. Although transthoracic echocardiography (TTE) is an excellent diagnostic tool in the ICU, TEE has superior diagnostic accuracy and therapeutic impact in several clinical situations, particularly for patients in shock states.13 Several authors have demonstrated that TEE findings lead to major therapeutic decisions between 43% and 68% of the time.1,46 Transesophageal echocardiography produces superior 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. 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 can account for this including inadequate patient positioning, lung hyperinflation, obesity, edema, and the presence of chest devices, wounds, and dressings. Transthoracic echocardiography 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, embolic sources, 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 similar sensitivity and specificity for suspected central pulmonary embolism (PE) associated with right ventricular dilatation.8,9

Many factors have combined to increase the use of TEE in the ICU.10

1. The increasing use of ultrasound and echocardiography in the ICU has made intensivist skills in these modalities more prevalent.

2. The presence of ultrasound units dedicated to the ICU has reduced the acquisition cost of TEE.

3. The perspective of TEE as a risky and invasive procedure requiring sedation with a risk of airway compromise is removed in mechanically ventilated and sedated ICU patients. Transesophageal echocardiography in ICU patients has had consistently low complication rates: 0% among three studies totaling 304 patients1,4,6 with two additional trials reporting rates of 1.6% and 2.6%.2,5 The most common complication is sedative-induced hypotension requiring additional vasopressor use.

4. Limited or goal-directed TEE examination is of significant value, yielding important information in a short period of time, with several authors reporting exam times of <15 minutes.4,11

5. Skill in performance and interpretation of limited TEE examination can be acquired by intensivists after as few as eight to 10 supervised TEE exams and one didactic session.4

In this chapter, an overview of the technical and performance aspects of TEE including discussion of the goal-directed TEE exam will be discussed.

Transesophageal echocardiography is a minimally ...

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