By Charles Draznin, MD, Peter Keenan, MD, and Mike Mallin, MD
Just Last Week from Mike Mallin:
A 75 year old male is brought in from the field in cardiac arrest. He had witnessed V-Fib arrest by EMS and received 3 total shocks en route with intermittent return of spontaneous circulation. On arrival to the ED, the patient is intubated and not receiving compressions, reported to be in sinus rhythm. After moving him over to the gurney, the airway is confirmed but a pulse cannot be palpated. “Restart chest compressions” says the physician as the patient is hooked up to a monitor and the provider attempts to visualize the heart with a bedside transthoracic echo (TTE) during the 2 minute pulse check, which elicits a narrow complex rhythm at 70. The provider struggles with the TTE for 10 seconds during the pulse check, but cannot obtain a view. No one can feel a pulse.
Compressions are recommenced. During this second round of compressions, the provider grabs and places the transesophageal echo (TEE) probe in the patient’s esophagus with a slight chin thrust and gentle pressure. Inserting the probe to about 16 cm he rotates then leaves the multiplane at 0 degrees and obtains a midesophageal 4 chamber view.
The chest compressions, which he can see immediately, are inadequate because they are compressing the right ventricle instead of the left ventricle with less than 4cm of sternal movement on echo. CLICK HERE FOR VIDEO.
He also notices that there is intrinsic cardiac activity. The heart is beating under the compressions. “Hold compressions,” he says as he notes a cardiac rate similar to the monitor, with a moderately decreased ejection fraction (EF). A pulse check is reattempted, this time with ample time and less stress for the healthcare workers to find the pulse. After about 45 seconds the nurse with his hand on the femoral artery notes, “I’ve got a pulse.” A blood pressure reads 85/62. An epinephrine drip is started, and with it, the improvement of EF is noted on TEE. Minutes later the patient disappears to the Cath lab.
Transthoracic echocardiography (TTE) is one of the standard ultrasound applications taught to emergency medicine residents. Evaluation of LV function, pericardial effusion, and right heart strain are increasingly familiar diagnostic questions for residents in training. Ultrasound fellows learn more advanced applications and techniques (valve pathology, regional wall motion abnormalities, diastolic dysfunction, cardiac output and volume responsiveness), but most still only have access to transthoracic scanning.
In many cases, the ability to obtain answers to these focused questions is impaired by any of multiple factors, including patient habitus, chest compressions, recent surgeries, chest wall trauma or pneumothorax. In these cases, a more direct approach to visualizing the heart can provide beneficial information.
The Emergence of TEE as an EUS Application
Transesophageal echocardiography (TEE) is widely used by certain other specialties such as cardiology and anesthesia, but its use is not yet widespread in the ED setting. Its use in the ED has been reported in a case series of patients in cardiac arrest as well as in E-book format.1,2 It has also been covered in the podcast format.3
A recent review article covering point of care cardiac ultrasound discusses a number of ED and ICU applications of TEE.4 Measurement of superior vena cava variation for determining fluid status and monitoring chest compressions are novel techniques not previously available with TTE. Serial measurements of cardiac function may be more easily allowed by a transducer that can be left in place for hours rather than needing to find a TTE window repeatedly.
Despite the increased information that can be quickly obtained, the use of TEE in the ED remains limited. Barriers to use have included cost, lack of training, perceived risk, and inter-departmental politics, among others. A recent query on the ACEP Ultrasound Fellows Google+ page regarding ED use of TEE garnered limited responses. While some posters mentioned simulator training, no fellows posted that they had current access to ED TEE.
Given that TEE is not widespread, but may be one of the upcoming technologies more commonly integrated into ED ultrasound practice, we’d like to hear your ideas on this topic. Please email us with your thoughts and comments. If you are using TEE, please let us know about your experiences (how and where you were trained, what types of patients you use it for, obstacles overcome in order to implement it). If you have comparison pictures and videos of TTE and TEE from the same patient, please consider sharing them. If you have not been able to use TEE, please describe the barriers and impediments that you’ve found.
1. Blaivas M. Transesophageal echocardiography during cardiopulmonary arrest in the emergency department. Resuscitation. 2008;78(2):135–40.
2. Introduction to Bedside Ultrasound: Volume 2. Mallin M and Dawson M. E-book.
4. Arntfield R, Millington S. Point of Care Cardiac Ultrasound Applications in the Emergency Department and Intensive Care Unit - A Review. Curr Cardiol Rev. 2012;8(2):98–108.
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