Complications resulting from intraoperative TEE can be separated into two groups: injury from direct trauma to the airway and esophagus and indirect effects of TEE (Box 10-3). In the first group, potential complications include esophageal bleeding, burning, tearing, dysphagia, and laryngeal discomfort. Many of these complications could result from pressure exerted by the tip of the probe on the esophagus and the airway. Although in most patients even maximal flexion of the probe will not result in pressure above 17 mm Hg, occasionally, even in the absence of esophageal disease, pressures greater than 60 mm Hg will result.

Further confirmation of the low incidence of esophageal injury from TEE is apparent in the few case reports of complications. In the world’s literature, there are only a few reports of a fatal esophageal perforation and benign Mallory-Weiss tear after intraoperative TEE.

The second group of complications that result from TEE includes hemodynamic and pulmonary effects of airway manipulation and, particularly for new TEE operators, distraction from patient care. Fortunately, in the anesthetized patient there are rarely hemodynamic consequences to esophageal placement of the probe and there are no studies that specifically address this question. One potential hemodynamic effect of TEE, even in the well-anesthetized patient, is direct cardiac irritation from the probe with resultant atrial and ventricular arrhythmias. More important for the anesthesiologist are the problems of distraction from patient care. Although these reports are infrequent in the literature, the authors know of several endotracheal tube disconnections that went unnoticed to the point of desaturation during TEE. Additionally, there have been instances in which severe hemodynamic abnormalities have been missed because of fascination with the images or the controls of the echocardiograph machine. Clearly, new echocardiographers should enlist the assistance of an associate to watch the patient during the examination. This second anesthesiologist will become unnecessary after sufficient experience is gained. It is also important to be sure that all of the respiratory and hemodynamic alarms are activated during the echocardiographic examination.

SAFETY GUIDELINES AND CONTRAINDICATIONS

To ensure the continued safety of TEE, the following recommendations are made. The probe should be inspected before each insertion for cleanliness and structural integrity. If possible, the electrical isolation should also be checked. The probe should be inserted gently and, if resistance is met, the procedure aborted. Minimal transducer energy should be used and the image frozen when not in use. Finally, when not imaging, the probe should be left in the neutral, unlocked position to avoid prolonged pressure on the esophageal mucosa.

Absolute contraindications to TEE in intubated patients include esophageal stricture, diverticula, tumor, recent suture lines, and known esophageal interruption. Relative contraindications include symptomatic hiatal hernia, esophagitis, coagulopathy, esophageal varices, and unexplained upper gastrointestinal bleeding. Despite these relative contraindications, TEE has been used in patients undergoing hepatic transplantation without reported sequelae.

TECHNIQUE OF PROBE PASSAGE

The passage of a TEE probe through the oral and pharyngeal cavities in anesthetized patients may be challenging at times. The usual technique is to place the well-lubricated probe in the posterior portion of the oropharynx with the transducer element pointing inferiorly and anteriorly. The remainder of the probe may be stabilized by looping the controls and the proximal portion of the probe over the operator’s neck and shoulder. The operator’s left hand then elevates the mandible by inserting the thumb behind the teeth, grasping the submandibular region with the fingers, and then gently lifting. The probe is then advanced against a slight but even resistance, until a loss of resistance is detected as the tip of the probe passes the inferior constrictor muscle of the pharynx. This usually occurs 10 cm past the lips in neonates to 20 cm past the lips in adults. Further manipulation of the probe is performed under echocardiographic guidance.

Difficult TEE probe insertion may be caused by the probe tip abutting the pyriform sinuses, vallecula, posterior tongue, or an esophageal diverticulum. Overinflation of the endotracheal tube cuff could also obstruct passage of the probe. Maneuvers that might aid the passage of the probe include changing the neck position, realigning the TEE probe, and applying additional jaw thrust by elevating the angles of the mandible. The probe may also be passed with the assistance of laryngoscopy. The probe should never be forced past an obstruction. This could result in airway trauma or esophageal perforation.

ANATOMY AND TRANSESOPHAGEAL ECHOCARDIOGRAPHY VIEWS

Multiplane Transesophageal Echocardiography Probe Manipulation: Descriptive Terms and Technique

The process of obtaining a comprehensive intraoperative multiplane TEE examination begins with a fundamental understanding of the terminology and technique for probe manipulation (Fig. 10-1).² Efficient probe manipulation minimizes esophageal injury and facilitates the process of acquiring and sweeping through 2D image planes. Horizontal imaging planes are obtained by moving the TEE probe up and down (proximal and distal) in the esophagus at various depths relative to the incisors (upper esophageal: 20 to 25 cm; midesophageal: 30 to 40 cm; transgastric: 40 to 45 cm; deep transgastric: 45 to 50 cm) (Table 10-1). Vertical planes are obtained by manually turning the probe to the patient’s left or right. Further alignment of the imaging plane can be obtained by manually rotating one of the two control wheels on the probe handle, which flexes the probe tip to the left or right direction or in the anterior or posterior plane. Multiplane probes may further facilitate interrogation of complex anatomic structures, such as the mitral valve (MV), by allowing up to 180 degrees of axial rotation of the imaging plane without manual probe manipulation.

Figure 10-1 Ways to adjust the probe. Top left, Probe movement in the esophagus. Top right, Scanning angles obtained by crystal rotation. Bottom left, Movement of the tip forward and back. Bottom right, Movement of the tip from side to side.

Table 10-1 The Comprehensive Intraoperative Multiplane Transesophageal Echocardiographic Examination

Probe Tip Depth (from lips): Upper Esophageal (20 to 25 cm)
View	Aortic arch: long axis
Multiplane angle range	0°
Anatomy imaged	Aortic arch; left brachiocephalic vein; left subclavian and carotid arteries; right brachiocephalic artery
Clinical utility	Ascending aorta and arch pathology: atherosclerosis, aneurysms, and dissections Aortic CPB cannulation site evaluation

View Aortic arch: short axis Multiplane angle range 90° Anatomy imaged Aortic arch; left brachiocephalic vein; left subclavian and carotid arteries; right brachiocephalic artery; main pulmonary artery and pulmonic valve Clinical utility

Ascending aorta and arch pathology: atherosclerosis, aneurysms and dissections; pulmonary embolus; pulmonary valve evaluation (insufficiency, stenosis, Ross procedure)

Pulmonary artery catheter placement

Probe Tip Depth: Midesophageal (30 to 40 cm) View Four chamber Multiplane angle range 0° to 20° Anatomy imaged

Left ventricle and atrium

Right ventricle and atrium

Mitral and tricuspid valves

Interatrial and interventricular septa

Left pulmonary veins: slight probe withdrawal and turning to left

Right pulmonary veins: slight probe withdrawal and turning to right

Coronary sinus: slight probe advancement and turning to right

Clinical utility

Ventricular function: global and regional