1. Correct Answer: A. Dysphagia

Rationale: There are numerous sites of potential injury during insertion and usage of the TEE probe. Some of the most common complications include hoarseness and lip injuries, which can occur in 12% and 13% of patients, respectively. Dysphagia occurs in 1.8% of patients. Dental injury, esophageal hemorrhage, and tracheal intubation are less likely, occurring in 0.1%, 0.03%, and 0.02% of patients, respectively. Other rare complications include bronchospasm, laryngospasm, and esophageal perforation. When obtaining patient consent for TEE, it is important to accurately portray these risks to the patient and evaluate the patient for comorbidities that put them at higher risk of complications.

1. Helberath JN, Oakes DA, Shernan SK, Bulwer BE, D’Ambra MN, Eltzchig HK. Safety of transesophageal echocardiography. J Am Soc Echocardiogr. 2010;23(11):1115-1127.

2. Correct Answer: D. Use lower gain during imaging

Rationale: This patient possibly experienced esophageal injury as a complication of TEE usage intraoperatively. The bioeffects of ultrasound are most dependent on signal intensity. Gain settings on ultrasound create an amplification of returning ultrasound signals during imaging processing. Therefore, additional gain on ultrasound will not create an increased risk of tissue damage. In order to minimize the risk of esophageal injury during TEE, numerous precautions should be taken. Keeping the probe unlocked, especially when advancing the probe, is critical, especially if the probe is accidentally in an ante- or retroflexed position during advancement. Additionally, the gastroesophageal junction is a vulnerable portion of the esophagus that is prone to injury, particularly because manipulation of the probe at this location applies tension to relatively fixed tissues. Finally, if the patient has esophageal pathology such as an esophageal stricture or esophageal varices, but a TEE is still deemed necessary, then a pediatric probe may be considered to reduce the risk of injury.

1. Helberath JN, Oakes DA, Shernan SK, Bulwer BE, D’Ambra MN, Eltzchig HK. Safety of transesophageal echocardiography. J Am Soc Echocardiogr. 2010;23(11):1115-1127.

3. Correct Answer: C. Esophagectomy

Rationale: According to the task force of TEE, although there are several relative contraindications to TEE, the only absolute contraindication agreed upon by the American Society of Anesthesiologists (ASA) members and consultants is previous esophagectomy or esophagogastrectomy. Only some members of the task force agree that several conditions should be absolute contraindications to TEE, including tracheoesophageal fistula, esophageal trauma, Zenker diverticulum, esophageal stricture, esophageal varices, and previous bariatric surgery. There is agreement that Barrett esophagus, hiatal hernia, unilateral vocal cord paralysis, dysphagia, and large descending aortic aneurysm are not absolute contraindications to TEE. Atlantoaxial disorders require caution during insertion of the probe to avoid excess neck extension.

1. An Updated Report by the American Society of Anesthesiologists and the Society of Cardiovascular Anesthesiologists Task Force on Transesophageal Echocardiography. Practice guidelines for perioperative transesophageal echocardiography. Anesthesiology. 2010;112:1084-1096. doi: 10.1097/ALN.0b013e3181c51e90.

4. Correct Answer: C. Pulmonic valve

Rationale: Carcinoid syndrome most often presents with right-sided, as opposed to left-sided, valvular lesions. Due to its anterior position, the pulmonic valve is more difficult than most cardiac structures to view with TEE, which sits posterior to the heart. It can be visualized with a right ventricular inflow-outflow view and ascending aorta short-axis view; however, its resolution is often poor. On TTE, the pulmonic valve can be visualized in the parasternal short-axis view at the level of the aortic valve. A gradient across the pulmonic valve can also be obtained in this view.

The descending aorta can be visualized by TTE, most commonly in the parasternal long-axis view, lying along the posterior surface of the heart. However, a more complete evaluation and higher resolution imaging of the descending aorta is possible with TEE. This is because the TEE probe lies close to the descending aorta in the esophagus, and ultrasound signals are not interrupted by lung tissue. The tricuspid and aortic valves can be visualized well with TTE and TEE, but resolution is usually superior on TEE.

1. Denault AY, Couture EJ, Sia YT, Desjardins G. Right ventricle, right atrium, tricuspid and pulmonic valves. In: Perrino AC, Reeves ST, eds. A Practical Approach to Transesophageal Echocardiography. 4th ed. Wolters Kluwer; 2019:345-380.

5. Correct Answer: C. Distal ascending aorta

Rationale: Due to the location of the trachea lying in-between the esophagus and the distal ascending aorta, a blind spot exists when imaging this portion with TEE. This can interfere with identification of proper placement of the aortic cannula during cardiac surgery, as well as evaluation of an aortic disease in this region. The proximal ascending aorta can be evaluated with ascending aortic long-axis (Figure 39.1A) and short-axis views, as this portion lies below the carina. The aortic arch can be visualized with aortic arch long-axis (Figure 39.1B) and short-axis views, but the complete imaging may be partially impaired by the blind spot created by the trachea. The descending aorta is visualized in the descending aortic short-axis (Figure 39.1C) and long-axis views by rotating the TEE probe to the left. As an additional note, the right pulmonary artery can usually be visualized in the ascending aorta short-axis view; however, the view of the left pulmonary artery can be incomplete due to interruption by the left main bronchus.

1. Luedi MM, Phillips MC. Chapter 18: Incorrect diagnosis of a type A aortic dissection attributed to motion artifact during computer tomographic angiography: a case report. In: 100 Selected Case Reports from Anesthesia & Analgesia. Wolters Kluwer; 2019.

2. Pruszczyk P, Torbicki A, Kuch-Wocial A, et al. Visualization of the central pulmonary arteries by biplane transesophageal echocardiography. Exp Clin Cardiol. 2001;6(4):206-210.

3. The comprehensive transesophageal echocardiography exam. In: Armstrong WF, Ryan T, eds. Feigenbaum’s Echocardiography. 8th ed. Wolters Kluwer; 2019:61-99.

6. Correct Answer: D. Midesophageal long-axis view

Rationale: Figure 39.2 demonstrates the aortic valve (AV) in the AV short-axis view. To calculate an accurate gradient across the valve, the Doppler beam should be parallel with flow across the AV (i.e., as close to 0° as possible). As the angle increases between the Doppler beam and AV flow, the measured velocity across the valve will be underestimated and the calculated gradient (4 × velocity²) will be further underestimated. Ideally, the beam should align within 0 to 15° of the actual jet. Echo views with the probe positioned near the apex of the heart and scanning cephalad toward the aortic valve are often the most accurate for AV gradient calculations. On TEE, the most common views for calculating the AV gradient are the deep transgastric (Answer A) and transgastric long-axis views, with the deep transgastric view being the most optimal for alignment of the Doppler beam. With TTE, visualization of the left ventricular outflow tract (LVOT) from the apical view (apical five-chamber view) provides the most optimal alignment. While the midesophageal long-axis view (Figure 39.4) allows for visualization of the LVOT and calculation of LVOT diameter, the angle between flow across the AV (green line) and the Doppler beam (white line) is larger, making calculation of the AV gradient inaccurate (Answer B).