Guidelines for the Use of Transesophageal Echocardiography (TEE) in the ED for Cardiac Arrest
Approved by the ACEP Board of Directors April 2017
The American College of Emergency Physicians (ACEP)
has developed these criteria to assist practitioners performing emergency
ultrasound studies (EUS) of the heart using transesophageal echocardiography
during cardiac arrest.
Ultrasound has been shown in cardiac arrest to
accurately identify the presence or lack of intrinsic cardiac activity and in
some cases the cause of arrest, including left ventricular failure, right ventricular
failure, pulmonary embolism, pericardial tamponade, and hypovolemia. These
findings can lead to life-saving changes in management such as administration
of IV fluids, blood products, vasopressors, thrombolytics, or performance of a
pericardiocentesis. For these reasons cardiac ultrasound is endorsed by ACEP
policy. However transthoracic echocardiography (TTE) has been shown to have
significant limitations in critically ill patients, particularly those in
cardiac arrest. TTE image acquisition is technically difficult due to ongoing
CPR, air in the stomach from bag masked ventilation, and the presence of
defibrillator pads. Furthermore, TTE imaging may prolong pulse checks and lead
to reduced coronary perfusion pressure due to inadequate CPR. Transesophageal
echocardiography (TEE) allows the emergency physician to maintain the standard
of an ultrasound-informed resuscitation in the scenario of cardiac arrest,
where TTE is significantly limited.
Identification of presence/absence of cardiac activity
Identification of cardiac rhythm
Evaluation of left ventricular function
Evaluation of right ventricular function
Identification of pericardial effusion/tamponade
Esophageal injury or stricture
Lack of a definitive airway
Cardiac EUS is a focused examination and does not evaluate all aspects
of cardiac function. Some findings that may contribute to hemodynamic
compromise but are generally considered outside of the scope of EUS include
valvular pathology, diastolic dysfunction, septal defects, intracardiac
thrombus or mass.
Examination of the heart may be technically limited by
Inability to pass the TEE into esophagus
Presence of excessive air in the esophagus
Excessive mitral annular calcification
When technical factors prevent an adequate examination, these
limitations should be identified and documented. As usual in emergency
practice, such limitations may mandate further evaluation by alternative
methods, as clinically indicated.
Images should be optimized to avoid foreshortening of the ventricles
and to include the appropriate structures for each view.
Pericardial effusions must be taken into clinical context, as small
effusions can cause tamponade if accumulated rapidly, while large effusions can
be well tolerated if they accumulate slowly.
Clotted hemopericardium may be isoechoic with the myocardium, making it
difficult to identify.420000
Right ventricular failure is not specific to pulmonary embolism, and
can be due to pulmonary hypertension or other etiologies such as right sided
Pleural effusions can be mistaken for pericardial effusions. Multiple
views should be used to corroborate findings.
Fat pads can be mistaken for pericardial effusions, but these are
hypoechoic rather than anechoic and limited to the anterior and apical regions
of the heart, not circumferential.
Qualifications and Responsibilities of the Clinician Performing the
Since 2001, clear and succinct
ultrasound credentialing recommendations in emergency medicine have been
specifically established by the ACEP Ultrasound Guidelines and recommend a
benchmark minimum of 25-50 quality-reviewed scans per modality to demonstrate
technical and interpretive ability. Conversely, for ultrasound guided
procedures, 10 quality-reviewed procedures with ultrasound guidance are
recommended. Along the same lines, the guidelines recommend a similar pathway
for “different techniques” (such as performing transvaginal ultrasound once
competency with transabdominal ultrasound has been achieved). Just as with
procedures, if performing a “different technique” for image acquisition, 10
quality-reviewed exams using that technique are required to establish
TEE credentialing is unique in this
regard, such that image interpretation will have already been achieved through
credentialing in transthoracic echocardiography. In this respect, TEE
credentialing is more a question of technical ability and image acquisition.
TEE is highly dependent on hand-eye coordination and reliant on image
acquisition, making proctoring and Standardized Direct Observational Tools
(SDOTs) ideal for this modality. For this reason, providers seeking
credentialing in transesophageal echocardiography of cardiac arrest applications
should have completed training and met competency standards in transthoracic
completed a minimum of 2-4 hours of TEE-specific
CME or didactics;
performed a minimum of 10 proctored TEE
examinations (including probe insertion) on live patients and simulation
completed a standardized assessment by a
credentialed TEE provider.
Specifications for Individual Examinations
General - Images are obtained and interpreted in real time. Video clips should
be recorded rather than still images. Particular attention should be paid to
capturing clips during pulse checks in order to evaluate the underlying cardiac
Real-time scanning technique.
Overview. The goals of this imaging protocol are to limit the complexity of the
exam and to maximize the efficiency of the exam and the information acquired.
Each of the three TEE views has an analogous TTE view with which emergency
physicians are already familiar.
Details of technique. The transesophageal probe has 4 possible
movements. Rotation can be performed by rotating the probe either clockwise or
counterclockwise. The large wheel causes flexion of the probe either anteriorly
(anteflexion) or posteriorly (retroflexion) while the small wheel causes
flexion left or right. The multiplane is controlled by two smaller buttons on
the TEE probe, and adjusts the beam angle anywhere between 0° and 180°. While
in the midesophageal position, a multiplane of 0° or 180° are both parallel to
the diaphragm while 90° would be perpendicular to the diaphragm. Probe
insertion should be performed cautiously, with care taken to avoid dental
trauma and never forced to avoid injury to the oropharynx or esophagus. Neck
flexion if possible may ease the passage of the probe if resistance is met.
The midesophageal 4-chamber view is the first most intuitive view to
obtain. After advancing the probe to the thoracic esophagus, the heart will
come into view and with the multiplane at 0-20° all four chambers can be
visualized. This view is analogous to the familiar apical 4 chamber view in TTE
and is defined by visualizing both the left and right ventricles and atria as
well as the tricuspid and mitral valves in the same plane. Some retroflexion of
the probe is usually necessary to avoid foreshortening of the ventricles. This
view is useful for evaluation of RV and LV systolic function as well as size,
and is the preferred view during a pulse check to visualize the presence or
absence of a perfusing rhythm.
The midesophageal long-axis view is obtained by leaving the probe in
the same location as the midesophageal 4-chamber, but increasing the multiplane
to between 110° and 160°. This view is analogous to the parasternal long-axis
view, as it is defined by visualizing the mitral and aortic valves in the same
plane along with the left atrium, left ventricle, and the outflow tract of the
right ventricle. This view is useful for evaluation of left ventricular
systolic function, and during compressions helps evaluate compression adequacy
and location, with quality compressions causing maximal compression of the LV
and opening of the aortic valve.
The transgastric short axis is obtained by first moving the multiplane
back to 0°, then advancing the probe into the stomach and anteflexing the probe
so that the left ventricle and right ventricle are visualized in cross-section.
This view is analogous to the parasternal short-axis in TTE, with the
difference being the location of the inferior wall closest to probe in TEE
rather than the anterior wall being closest to the probe as in TTE. This view
is useful for providing additional information regarding LV systolic function,
evaluation of regional wall motion abnormalities that can suggest acute
myocardial infarction, and the presence of septal flattening that can indicate
increased right ventricular pressures.
EUS of the heart should be
obtained and interpreted by the treating physician and used to guide
decision-making in real time. These findings should be documented in the
medical record. Documentation should include the indication, description of the
exam performed, and pertinent findings. Images should be stored as part of the
medical record in accordance with facility policy requirements.
A phased array TEE probe should be used with
multiplane capability. Compatibility with the emergency department’s existing
point of care ultrasound equipment is important to ensure prior to purchase.
Quality Control and Improvements, Safety, Infection Control and Patient
Since TEE probes come into contact
with mucous membranes, a high level of disinfection is required after use.
Policies and procedures related to quality, safety, infection control and
patient education should be developed in accordance with existing hospital
policies for TEE probes.