Sansan S. Lo, Jeremy S. Poppers, Teresa A. Mulaikal, David J. West, Michelle M. Liao and Jack S. Shanewise

TEE: Indications, Complications, Probe Insertion, and Manipulation

The clinical utility of transesophageal echocardiography (TEE) has expanded since its introduction into the perioperative setting in the 1980s. TEE is a versatile tool that can be used to assess cardiac function and diagnose unanticipated problems. The American Society of Anesthesiologists (ASA) and the Society of Cardiovascular Anesthesiologists (SCA) issued guidelines for the intraoperative use of TEE in 1996 in which indications for intraoperative TEE fall under three categories. ¹ Category A includes clinical scenarios for which supportive literature suggests that TEE is strongly beneficial for clinical evaluation. Examples include valve repair, congenital heart defects, hypertrophic obstructive cardiomyopathy, aortic dissection, infective endocarditis, and unstable hemodynamics. Category B indications for TEE are those for which there is suggestive evidence for a benefit, and include myocardial ischemia, valve replacement, cardiac aneurysms, and intracardiac tumors. Category C indications are those for which there is equivocal literature, and include myocardial perfusion, monitoring for emboli during orthopedic procedures, and placement of intraaortic balloon pumps and pulmonary artery catheters. These guidelines were revised in 2010 and now state that in adult patients without contraindications, TEE should be used in all open (e.g., valvular) heart and thoracic aortic surgical procedures and should be considered for coronary artery bypass graft surgeries to: (1) confirm and refine the preoperative diagnosis, (2) detect new or unsuspected pathology, (3) adjust the anesthetic and surgical plan accordingly, and (4) assess the results of surgical intervention. ²

Although TEE is considered relatively safe and noninvasive, the TEE probe may cause oropharyngeal, esophageal, or gastric trauma. Other TEE complications may include dental trauma, laryngeal dysfunction, postoperative aspiration, endotracheal tube displacement, and upper gastrointestinal bleeding. In infants, bronchial and aortic compression are also possible. Therefore, prior to TEE, the medical history should be aimed at eliciting a history of esophageal disease, dysphagia, and hematemesis. Past medical history should be reviewed as well. Relative contraindications to TEE include a history of dysphagia, odynophagia, mediastinal radiation, recent upper gastrointestinal surgery, recent upper gastrointestinal bleeding, thoracic aortic aneurysm, esophageal stricture/tumor/diverticula/varices, esophagitis, and recent chest trauma. In patients with distal esophageal or gastric pathology, efforts should be made to obtain needed information without advancing the TEE probe into the distal esophagus. Preoperative esophagoscopy can also be considered when risk of TEE is unclear.

Prior to TEE probe insertion, it may be useful to suction esophageal and gastric air through an orogastric tube. Then, using the left hand to perform a jaw thrust, the mandible is displaced anteriorly, and the right hand is used to insert a lubricated TEE probe toward the posterior pharynx along a midline axis and advanced into the esophagus. Although a mild degree of resistance is frequently experienced as the probe passes the upper esophageal sphincter, probe insertion and manipulation should always be performed gently, and excessive force should never be used. If necessary, laryngoscopy can be performed to displace the mandible and better visualize the esophageal opening. Flexion of the neck may facilitate insertion of the TEE probe, whereas extension may make it more difficult. Once the probe reaches the level of the thoracic esophagus (≈30 cm from incisors), the heart should come into view on the screen. On the rare occasion that the probe cannot be placed into the esophagus despite multiple attempts by qualified practitioners, TEE placement should be abandoned to avoid harm to the patient.

When imaging the heart with TEE, the structure visualized depends on the probe’s position between the upper esophagus and stomach and the direction of the ultrasound beam. For example, in the upper esophagus, midesophagus, and transgastric positions, the structures closest to the TEE probe are the great vessels, left atrium, and left ventricle, respectively, and will be displayed at the top, or vertex, of the imaging sector.

The TEE probe can be manipulated and adjusted to optimize visualization of cardiac anatomy ( Fig. 1-1). The wheels of the probe should be unlocked and in neutral position prior to movement to prevent trauma. The probe can be advanced or withdrawn within the esophagus, and the orientation of the ultrasound beam can be manipulated by rotating the probe to the patient’s left (counterclockwise) or right (clockwise). Turning the large control wheel clockwise will anteflex the probe (flex the tip anteriorly), whereas counterclockwise turning will retroflex (flex posteriorly) it. The small knob will flex the probe leftward or rightward. With a multiplane TEE probe, the transducer angle can be rotated axially from 0 (horizontal) to 90 (vertical) to 180 degrees (mirror image of 0 degrees horizontal plane) while the tip remains in a fixed position. Orienting oneself with respect to the ultrasound beam and the image displayed on the screen may be a source of confusion. An easy method often employed to orient the echocardiographer utilizes the right hand, with its thumb pointing to the left and palm facing the floor. With the patient in supine position, the operator stands at the head, facing the patient’s feet. In this position, the fingers represent the ultrasound beams as they extend perpendicularly from the head of the probe, and the thumb will point toward the left-sided structures that appear on the right side of the screen at 0 degrees. As the multiplane angle is increased to 90 degrees, the right hand is rotated clockwise until the thumb points toward the ceiling and now demonstrates anterior structures of the heart on the right side of the screen; inferior structures are displayed on the left side of the screen.

The Twenty Standard Views

In 1999 the American Society of Echocardiography (ASE) and SCA published guidelines for performing a comprehensive intraoperative TEE examination that described and named 20 TEE views that comprise a complete routine examination. ³ These 20 views are summarized in Table 1-1 and described in the sections that follow.

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