Common pitfalls in point-of-care ultrasound: a practical guide for emergency and critical care physicians

Abstract

BackgroundPoint-of-care ultrasonography (POCUS) is a widely used tool in emergency and critical care settings, useful in the decision-making process as well as in interventional guidance. While having an impressive diagnostic accuracy in the hands of highly skilled operators, inexperienced practitioners must be aware of some common misinterpretations that may lead to wrong decisions at the bedside.ObjectivesThis article provides a revision list of common POCUS misdiagnoses usually found in practice and offers useful tips to recognize and avoid them.DiscussionThe following aspects were selected and reviewed: pericardial effusion vs. pleural vs. ascites vs. epicardial fat; right ventricle dilation in acute pulmonary embolism and inferior vena cava for volume status assessment in cardiac ultrasound; lung point and lung pulse misinterpretations and mirror artifacts vs. lung consolidations in lung ultrasound; peritoneal fluid vs. the stomach and a critical appraisal of gallbladder signs of acute cholecystitis in abdominal ultrasound; the rouleaux phenomenon vs. deep vein thrombosis or acute right strain in vascular ultrasound.ConclusionsFollowing some rules in technique and interpretation, and always integrating POCUS findings into the broader clinical context, most POCUS misdiagnosis can be avoided, and thus patients’ safety can be enhanced. Being aware of a list of common pitfalls may help to avoid misdiagnoses.Electronic supplementary materialThe online version of this article (doi:10.1186/s13089-016-0052-x) contains supplementary material, which is available to authorized users.

Partially thrombosed aneurysm of the medial marginal vein

“…Rouleaux formation is a reversible phenomenon that results from aggregation of red blood cells during low blood flow and small shear forces. While normally flowing blood is anechoic due to small size of the red blood cells, stacked red blood cells become mobile ultrasound reflectors and appear as intermediate echoes . Unlike mural thrombi, the formed rouleaux are mobile and, hence, the lumen remains fully compressible.…”

When appearances deceive: Echocardiographic changes due to common chest pathology

“…Small pleural effusions may be difficult to detect but larger effusions (Figure A) are often found incidentally during a standard transthoracic echocardiography. When detected by incidence, a pleural effusion usually represents a clinically relevant amount of fluid …”

“…A left‐sided pleural effusion may be seen close to the descending aorta and the left atrium but will appear on the same side of both structures, ie, either posteriorly in PLAX or laterally in the apical four‐chamber view. Conversely, pericardial effusions, if sufficiently large, may separate the descending aorta from the left ventricle and may be identified throughout the entire circumsphere of the heart . These signs may not be clear‐cut and supplementary lung ultrasonography may help to distinguish between pleural and pericardial effusions (Table ).…”

“…When detected by incidence, a pleural effusion usually represents a clinically relevant amount of fluid. 105 Due to its close proximity to the pericardial sack, pleural effusion is occasionally misdiagnosed as pericardial effusion. Distinction between the two kinds of effusions is essential to avoid non-indicated pericardiocentesis ( Figure 5A,B).…”

“…Conversely, pericardial effusions, if sufficiently large, may separate the descending aorta from the left ventricle and may be identified throughout the entire circumsphere of the heart. 105 These signs may not be clear-cut and supplementary lung ultrasonography may help to distinguish between pleural and pericardial effusions ( Table 1).…”