Echocardiography is the gold standard for the diagnosis of many cardiac and pericardial abnormalities.1 Echocardiography provides critical information about cardiac structure and function in real time. Since it is impossible for expert echocardiographers to be present in a timely manner for most critical resuscitations, emergency physicians have begun to incorporate focused bedside echocardiography into their daily clinical practice.2–7 During the past 20 years, there is a growing body of evidence that noncardiologists can use focused echocardiography safely and accurately in a variety of clinical settings.5, 8–23
Focused echocardiography is a goal-directed examination that is used only to answer defined clinical questions and not to detect all possible cardiac pathology. The key is to keep the examination straightforward by evaluating for gross abnormalities and overall cardiac function.2, 24, 25 Focused echocardiography is not meant to replace comprehensive echocardiographic examinations; rather, its purpose is to provide clinicians with vital, real-time information when comprehensive echocardiography is unavailable.24, 26
Focused transthoracic echocardiography is an ideal diagnostic tool for detecting life-threatening cardiac conditions in the emergency department. Much of the information obtained from a focused bedside echocardiographic examination could also be obtained by invasive monitoring techniques. Although emergency physicians and critical care physicians routinely use invasive monitoring, it is not practical to use invasive techniques on all patients with potentially life-threatening conditions. Patients who have quickly reversible hemodynamic compromise do not need invasive monitoring. In addition, placement of invasive monitoring devices is time consuming and has complications.
Without bedside echocardiography or invasive monitoring, clinicians would be left to manage critically ill patients with only indirect information about cardiac structure and function. “Classic” physical examination findings and changes in vital signs are often absent and unreliable for making critical diagnoses. An electrocardiogram (ECG) is very helpful in patients with certain cardiovascular problems who have diagnostic findings, but the majority of critically ill patients have nonspecific ECG findings. A chest radiograph may also provide some helpful information, but is just as likely to be nonspecific as well.
In cardiac arrest with pulseless electrical activity (PEA), it is critical to determine whether the patient has true electromechanical dissociation (EMD) with cardiac standstill or pseudo-EMD with mechanical cardiac contractions too weak to generate a palpable blood pressure.27 Some patients thought to be in cardiac arrest have extreme hypotension. Other patients with PEA have cardiac tamponade, massive pulmonary embolism (PE), or severe left ventricular dysfunction. All of these conditions can be detected with bedside transthoracic echocardiography. Echocardiography can be performed serially during a critical resuscitation as long as the examination itself does not interfere with resuscitative efforts.
A controversial use of focused echocardiography is for patients who are stable and minimally symptomatic. Stable patients presenting with nonspecific symptoms may benefit from a focused echocardiographic examination. Pericardial effusions often cause nonspecific or minimal symptoms until tamponade develops. Focused echocardiography is the most efficient ...