Echocardiography is the gold standard for the diagnosis of many cardiac abnormalities. Point-of-care echocardiography (or focused cardiac ultrasound), performed and interpreted by clinicians, was described 25 years ago.1–3 Since then, there has been a significant amount of accumulated data to demonstrate that this practice changes management and improves patient care.4–73 Clinician-performed echocardiography is now a well-accepted part of the practice of emergency medicine.43,74,75 In addition, clinicians who manage critically ill or injured patients in other clinical settings are adopting the practice of focused cardiac ultrasound.76–115
Focused cardiac ultrasound is not meant to replace comprehensive echocardiography; it is a completely different paradigm in which a goal-directed examination is meant to answer specific clinical questions, not to detect all possible cardiac pathology. Some clinicians may use cardiac ultrasound to answer just one clinical question and others may use it for a wide variety of applications. Regardless, most focused cardiac ultrasound applications are relatively straightforward to learn because they rely on simple two-dimensional (2D) imaging and pattern recognition.116
Focused transthoracic echocardiography is an ideal diagnostic tool for detecting life-threatening cardiac conditions in the ED. Some of the information obtained from focused cardiac ultrasound could be obtained by invasive monitoring techniques, but it is not practical to use invasive techniques on all patients with potentially life-threatening conditions. In addition, placement of invasive monitoring devices is time consuming and is associated with complications.
Without bedside echocardiography, clinicians are left to manage critically ill patients with only indirect information about cardiac structure and function. “Classic” physical examination findings are often absent and unreliable for making critical diagnoses. Electrocardiograms (ECGs) are very helpful in patients with certain cardiac problems, but the majority of critically ill patients have nonspecific ECG findings. Chest radiographs provide very limited information about cardiac structure and function.
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.117 Many patients with PEA have severe hypovolemia, while others 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.
Point-of-care cardiac ultrasound is also useful in stable patients with a wide variety of presentations. Pericardial effusions often cause nonspecific or minimal symptoms until tamponade develops. Focused echocardiography is the most efficient method to evaluate for a “silent” pericardial effusion since it is not reasonable to order a comprehensive echocardiographic examination on every patient with vague complaints who may have a pericardial effusion. Also, about 6% of all patients over 45 years of age have “silent” heart failure.118,119...