Traditionally, ultrasound of the heart was the sole domain of the cardiologist. As a community, cardiologists have been resistant to accept a non–cardiologist-performed echo for fear of false information being obtained, and patients subsequently suffering from misdiagnosis or misguided interventions. This is reflected in the early American Society of Echocardiography guidelines from 1999 [8]. In this policy statement there is a clear concern that even simple conditions, like cardiac tamponade, may be misdiagnosed or misinterpreted by non-cardiologist sonographers. In their summary statements, it is recommended that all emergency departments collaborate with more experienced echo providers and that systems be established to limit gaps in coverage by a trained sonographer. In the situation of a life-threatening condition like tamponade, if the sonographer was not immediately available, they hesitantly supported the concept of a lesser trained physician acquiring and interpreting initial images with subsequent review by a sonographer as soon as possible.

In 2010 a combined statement between the American Society of Echo and the American College of Emergency Physicians describe a much more collaborative approach. In this statement it is suggested that the term focused cardiac ultrasound (FOCUS) be used to describe point-of-care evaluations , allowing differentiation between a comprehensive TTE, performed by a cardiologist, a limited echo (performed by a cardiologist but without all images obtained) and FOCUS performed by a non-cardiologist [9]. They state that the goal of focused sonography in symptomatic emergency patient is limited. Specifically, the focused exam, per their guidelines, should be used in assessing for cardiac tamponade or effusion, global left and right heart function, and an intravascular volume. In the cases of effusion or tamponade, ultrasound can be also used for guidance of pericardiocentesis.

Flash forward to 2013 and the most recent policy statements of the American Society of Echo, where clearly a softer attitude towards FOCUS exists [10]. With the proper definitions of comprehensive echo, limited echo, and focused ultrasound having been delineated, the American Society of Echo seems to have accepted the role of FOCUS as an adjunct to the physical exam in the emergency setting, off hours, or when formal echo is not available. These guidelines state that focused cardiac ultrasound should be used only for specific situations and answering specific questions, with the intent that follow up formal echo will be performed to confirm findings as well as identify associated findings that would likely go unrecognized by the focused exam.

There are a variety of important applications of FOCUS , and there is substantial emergency medicine literature supporting its use in bedside decision making, even without confirmatory imaging by a cardiologist [2, 11]. For example independent assessment of the heart in the setting of blunt and penetrating trauma has been the standard of care since the introduction of the FAST exam in the 1990s [12]. The subxyphoid view of the heart for pericardial fluid is an integral part of the initial assessment in trauma patients. Furthermore the presence or absence of cardiac findings on this exam decreases time to diagnosis, treatment, and has been shown to improve mortality [13, 14].

In addition cardiac ultrasound commonly used during ACLS as it can be used to differentiate between PEA, asystole, and profound hypotension [15, 16]. Furthermore, FOCUS in conjunction with other ultrasound imaging can be used in identifying a pulmonary embolus, pneumothorax, or tamponade as treatable causes of the arrest. Also, the presence or absence of cardiac activity on this exam decreases time to diagnosis, treatment, and has been shown to improve mortality [13, 14].

Follow-up formal echocardiography is indicated at the treating physician’s discretion. The underlying points of the American Society of Echo’s recommendations are well taken, but more often than not action is required before confirmatory testing can be obtained. In addition cardiologists are trained in echo for a specific application; to evaluate the heart. But many of the applications of echocardiography in the ICU and emergency department employ it as a tool to guide resuscitation. It is more about optimizing end organ perfusion, or determining the cause of shock, than it is about managing heart failure or diagnosing valvular dysfunction. Often it involves imaging other organs, and a knowledge base in resuscitation in addition to an understanding of cardiac physiology. A new form of echo has evolved, and it is possible that cardiologists are not the best trained at interpreting it simply because they initially developed the field. Ideally cardiologists, emergency medicine physicians, intensivists, and surgeons would share resources and work for the common good of the patients, but when that is not the case, patients’ needs and advancing medicine trump territoriality.

There is a spectrum in the complexity of focused cardiac ultrasound, from answering simple binary questions, to some objective flow and volume measurements, to exams that rival formal echo [4, 11, 17]. Regardless, the technical approach to the cardiac exam is essentially unchanged (Fig. 3.7). It is often necessary to look ‘through’ the ribs, and for this reason a phased array or small footprint probe is best. In addition, the best fidelity imaging will be obtained on a cardiac quality machine, with a full service cardiac software package. If this is not available, it is still possible to obtain images and evaluate basic cardiac function, with any low frequency transducer.

The parasternal long axis (PLA) view is obtained with the patient supine or in a slight left lateral position to improve image acquisition. The transducer is placed on the chest, just left of the sternum at the 3rd or 4th intercostal space. It is oriented towards the right mid-clavicular line, and can be moved up or down with the goal of bisecting the left ventricle on its long axis. The heart is often lower and more medial in intubated patients (Fig. 3.8) With this view, one can see the left ventricle, the mitral and aortic valves in cross section, and some of the right ventricle. It is easy in this view to assess the contractility of the left heart, and to assess for effusions, both pericardial and pleural (Fig. 3.9).

The short-axis window (SA), is obtained after the PLA, by rotating the probe 90° clockwise to bisect the left mid-clavicular line. The SA provides a cross-sectional view across the left ventricle. The probe can be swept along the heart to obtain views through the aortic valve, mitral valve, papillary muscles, and apex of the heart (Fig. 3.10). The SA is excellent for evaluating ejection fraction (EF), as well as right heart function. With right heart failure, one will see a large right heart, and D-shape of the left heart with diastole (Fig. 3.11). Ejection fraction (EF) can by quantified in both the PLA and SA, but is best assessed after viewing all four windows. Both the PLA and SA can be obtained in greater than 90 % of patients [18], and the EF can be assessed in > 90 % as well [4].

The apical (AP) view is obtained by placing the transducer near the apex of the heart, usually located a few centimeters below the nipple between the left mid-clavicular and anterior axillary lines. The grove is rotating about 45° clockwise from the SA, and aimed towards the bed. Turning the patient with the right side up can sometimes bring the heart closer to the chest wall making it easier to see. The maneuver is not as effective in mechanically ventilated patients, but it can be helpful in extubated patients The AP window gives a view that bisects the heart in an anterior-posterior orientation. The AP 4-chamber is usually the first view allows excellent visualization of the right atrium (RA), RV, left atrium and LV, then by rocking the transducer head anteriorly the 5-chamber view is obtained. The 5-chamber view allows visualization of the left ventricular outflow tract to the aorta (Fig. 3.12). This view is important for assessing for aortic stenosis, in conjunction with the PLA. It is also essential in calculating the stroke volume (SV) and cardiac index (CI) [4]. The apical windows are ideal views for assessment EF, right heart function, and get a global assessment of right heart size. Normally, the RV is 60 % the volume of the LV [18]. If this ratio is higher, or the right heart is larger than the left, and implies right heart overload or failure, although this may be different in mechanically ventilated patients. We have found in the majority of ventilated the RV appears equal to or slightly larger than the LV although the function appears normal. The apical windows are also essential in obtaining the measurements described in below in the hemodynamic echocardiography section below.