the adult patient, their relative clinical importance makes cardiac ultrasound an invaluable tool when examining pediatric patients with these conditions Evaluating global cardiac function and volume status can also have an immediate impact on patient care These echocardiographic skills however, are more difficult to acquire and beyond the scope of this chapter Consequently, practitioners should know their limits and use ultrasound accordingly The purpose of focused echocardiography is to provide the clinician with immediate bedside information and is not meant to replace comprehensive, cardiology-performed echocardiograms Numerous studies of both adult and pediatric patients have shown that physicians can accurately identify pericardial effusions in the setting of both traumatic and nontraumatic etiologies In penetrating chest trauma, early identification of pericardial effusion dramatically improves patient outcomes In adult patients with cardiac arrest, those with PEA who have cardiac activity demonstrated on POCUS are more likely to survive when compared with patients with cardiac standstill POCUS may also identify life-threatening causes of PEA such as cardiac tamponade Because cardiac arrest is such a rare event in children, prospective studies have not been performed, and single-institution investigations may not be fruitful Anatomy The standard terminology used in other ultrasound examinations is less useful when discussing cardiac ultrasound because of the position of the heart within the thorax Instead, standard views are along two different cardiac planes The cardiac long axis views the heart along its plane from the atria to apex The short axis cuts across the heart from anterior to posterior, along the plane from the right hip to the left shoulder (Fig 131.8 ) These axes form the basis for the standard cardiac views used in emergency POCUS Technique The subxiphoid view is the same view as obtained when performing the FAST examination A low-frequency (2- to 5-MHz) curvilinear or phased array probe should be chosen Phased array probes are better for moving structures such as the heart Smaller footprint probes may prove useful when attempting cardiac views between the rib spaces of pediatric patients FIGURE 131.8 Ultrasound axes of the heart LA, long axis; SA, short axis Some controversy still exists in emergency medicine as to the direction of the probe marker and location of the marker indicator on the monitor We have generally found that for the novice sonographer, keeping the marker indicator or “dot” on the left side of the screen and marker toward the patient’s right for the subxiphoid four-chamber view maintains consistency and convention Classic echocardiography dictates the opposite approach, with the probe marker directed leftward and the marker indicator on the right side of the machine In both instances, the same image orientation will appear on the screen Recall that the heart lies obliquely in the chest, with the apex pointed toward the left hip The subxiphoid view cuts across the heart from its atria to apex and is thus considered a long-axis image The transducer position is the same as for the cardiac portion of the FAST examination, and should lie almost parallel to the abdomen, just below the xiphoid process with the probe angled toward the left shoulder (Fig 131.6 ) The probe can be slid rightward along the inferior portion of the last rib to avoid the acoustic artifacts caused by air in the stomach, using the liver as an acoustic window As the ultrasound beam moves toward the left shoulder from the subxiphoid space, it will encounter the liver first, then right ventricle (RV) and right atrium (RA), followed by the left ventricle (LV) and left atrium (LA) The image obtained will correlate such that the liver is at the top of the screen and the left ventricle is near the bottom of the screen (Fig 131.7 ) Normally, the bright white pericardium abuts the gray myocardium When a pericardial effusion is present, a hypoechoic or anechoic (dark) stripe will appear between the two (Fig 131.9 , Video 131.8 ) The left parasternal long view is obtained by placing the probe in the third or fourth intercostal space, immediately left of the sternum, with the marker pointed toward the left hip Unlike the subxiphoid view in which the probe lies almost flat against the chest, it should instead be placed perpendicular to the chest wall in the parasternal long view (Fig 131.10 ) The image acquired should cut across the long axis of the heart, from the atria (right shoulder) to apex (left hip) This view can be quite useful in obese patients, in whom the subxiphoid view is often difficult to obtain Just as in the subxiphoid view, the right ventricle is the first cardiac structure encountered by the ultrasound beam, as it lies most anterior and closest to the probe (Fig 131.11 , Video 131.9 ) FIGURE 131.9 Pericardial effusion: an anechoic fluid collection (F) surrounds the myocardium Note the liver (Li), right ventricle (RV), and left ventricle (LV) The subxiphoid and parasternal long views are the most useful when assessing for cardiac activity or pericardial effusions Other cardiac windows include the parasternal short view and apical four-chamber view The parasternal short-axis view can be obtained in a similar location on the chest wall as for the parasternal long-axis view but with the probe oriented along the short axis of the heart (from the patient’s left shoulder to the right hip) This view can easily be obtained by starting in the parasternal long axis and simply rotating the probe 90 degrees until the probe marker is pointing toward the patient’s right hip The image acquired in this plane gives a cross-sectional, circumferential view of the left ventricle and, for the advanced cardiac ultrasonographer, can be used to assess contractility ( Video 131.10 ) ... Ultrasound axes of the heart LA, long axis; SA, short axis Some controversy still exists in emergency medicine as to the direction of the probe marker and location of the marker indicator on the