Echocardiography has been a component of emergency medicine practice for over 20 years, and serves as an integral diagnostic tool in the evaluation of patients with cardiac and noncardiac disorders. Echocardiography represents the only diagnostic modality capable of providing real-time bedside information for acutely ill patients in the emergency department (ED). In addition to cardiac anesthesiologists and cardiologists, trainees in U.S.-based emergency medicine residency and fellowship programs now often acquire specialized training in echocardiography.
Transthoracic echocardiography (TTE) has proven to have several applications in routine clinical practice including the detection of cardiac effusion and tamponade, estimating cardiac ejection fraction, and as an important adjunct during specialized procedures such as pericardiocentesis.1,2 Under certain circumstances, however, TTE may be impractical (ie, during active chest compressions in the arresting patient), impossible (ie, in the morbidly obese patient), or inadequate (ie, definitive imaging of the ascending aorta). In such cases, transesophageal echocardiography (TEE) may be a suitable alternative, and in some cases can be regarded as the first-line echocardiographic investigation. While TEE is still primarily under the purview of the cardiologist or cardiac anesthesiologist, suitably trained emergency medicine physicians have also begun to incorporate TEE into their practice. Regardless, physicians using TEE as a tool for clinical management need to be adequately trained in performance and interpretation, which has prompted the American Society of Echocardiography to publish a policy statement on echocardiography in the ED.3
- Guidelines for the clinical application of echocardiography in the ED. The ACC/AHA/ASE guidelines for the clinical application of echocardiography (2003) have established recommendations for the use of echocardiography in the critically ill or injured patient (Table 23–1), including that echocardiography is appropriate to use in patients with suspected aortic injury, hemodynamically unstable patients, patients with serious blunt or penetrating chest trauma, and suspected pre-existing valvular or myocardial disease in the trauma patient. Table 23–2 details the specific clinical conditions and diagnoses for which echocardiography can be a useful diagnostic tool in the ED.
- Transthoracic versus transesophageal echocardiography in the ED. The ACC/AHA/ASE guidelines for the clinical application of echocardiography (2003) have also delineated the conditions and settings in which TEE (as opposed to TTE) provides the most definitive diagnosis in critically ill or injured patients, including the hemodynamically unstable patient with suboptimal TTE images or those on ventilators; major trauma or postoperative patients; suspected aortic dissection or other aortic injury; and other conditions in which TEE is superior (ie, endocarditis and cardiac source of emboli).4
Table 23–1. ACC/AHA/ASE Guidelines for the Clinical Application of Echocardiography in Critically Ill and Injured Patients. ||Download (.pdf)
Table 23–1. ACC/AHA/ASE Guidelines for the Clinical Application of Echocardiography in Critically Ill and Injured Patients.
|• Hemodynamically unstable patient|
|• If suboptimal images or on ventilator, then TEE|
|• Suspected aortic dissection (TEE)|
|• Serious blunt or penetrating chest trauma (suspected pericardial effusion or tamponade)|
|• Mechanically ventilated multiple-trauma ...|