Point-of-Care: Ultrasound

Point-of-Care: Ultrasound

Point-of-Care: Ultrasound >> https://urlin.us/2tDPro

Point-of-care ultrasound refers to the practise of trained medical professionals using ultrasound to diagnose problems wherever a patient is being treated, whether that's in a modern hospital, an ambulance, or a remote village. When Sonosite introduced the Sonosite 180 twenty years ago, it enabled clinicians to treat patients faster, more accurately, and in a non-invasive way at the point of care, without relying on trips to the Radiology department.

We believe the best chance a patient has at getting better is a clinician at their side with the right answers and the confidence to act. That's why we offer ultrasound education when and where you want it. Visit our Education page to get started learning about ultrasound-guided exams and applications today.

With the ever-changing landscape of health care delivery in the United States, a greater proportion of patients are receiving their initial care and diagnostic testing in emergency departments (EDs). With this change, significant efforts have been made to improve the speed and accuracy of diagnostic testing, particularly by using point-of-care testing, to minimize the delay between onset of symptoms and initiation of definitive therapy. Expediting triage and time to diagnosis are crucial to decreasing morbidity and mortality in critically ill patients.1 Point-of-care testing has been shown to achieve these goals, leading to improved operational efficiency and, ultimately, better patient outcomes.2 Point-of-care ultrasound (PoCUS) in the ED is one of the point-of-care testing tools available to the emergency physician. It answers specific clinical questions that narrow differentials, guide clinical therapy, and direct consultations and disposition. This review is meant to highlight major clinical scenarios in which PoCUS can be used as a rapid, reliable, diagnostic tool. This list of scenarios is just an overview; there are many additional situations in which PoCUS can be crucial, but the presentations are often less acute (for example, musculoskeletal complaints, procedural guidance, and pregnancy evaluation).

Broadly defined, shock is a state of tissue hypoxia due to reduced oxygen delivery, increased oxygen consumption, or inadequate oxygen utilization and most commonly occurs as a result of circulatory failure, resulting in hypotension. Identifying the cause of shock and rapidly intervening in patients experiencing it is an essential step in improving patient outcomes. PoCUS in the undifferentiated shock patient allows for rapid and accurate differentiation between the major shock types: distributive (i.e., septic), cardiogenic, hypovolemic (i.e., bleeding or other volume loss), and obstructive. There are several scan protocols that standardize this assessment, and most involve ultrasound imaging of the heart, the lungs, the vena cava, and a focused assessment of the abdomen to look for free fluid. Previous research on the use of PoCUS in the undifferentiated hypotensive patient presenting to the ED showed that despite taking only a short period of time (average of 6 minutes), the use of PoCUS led clinicians to significantly narrow their differential diagnosis and increase overall diagnostic precision.3 The sonographic footprint for each type of shock guides resuscitation efforts and interventions (see Table 1), such as fluid versus vasopressor support and therapeutic procedural interventions (for example, pericardiocentesis and laparotomy).

Despite the most recent international consensus on advanced cardiac life support conclusion that \"there is insufficient evidence to support or refute the routine use of ultrasound or echocardiography to guide cardiac arrest resuscitation,\"4 PoCUS has become a common prognostic and diagnostic tool during cardiac resuscitation, particularly when combined with rhythm strip data. In patients with pulseless electrical activity (PEA) in particular, PoCUS can prove immensely helpful in revealing anatomic causes of PEA such as tension pneumothorax (see Video 1), cardiac tamponade, and pulmonary embolism. Presence of increased right ventricular strain, new tricuspid regurgitation, pericardial effusion, or absence of lung sliding can point in the direction of a reversible cause of PEA, thus rapidly directing the emergency physician to perform tube thoracostomy, pericardiocentesis, or thrombolysis, for example.

The role of PoCUS for trauma patients has been a topic of considerable change and debate over the last 30 years. Using ultrasound as a diagnostic tool for traumatic abdominal/thoracic injuries started in Europe and spread to North America in the 1990s.8 Currently, ultrasound in trauma is primarily used for detection of intraperitoneal hemorrhage, pericardial tamponade, and hemothorax/pneumothorax. This constellation of applications is commonly referred to as the \"extended focused assessment with sonography for trauma\" (FAST).9 The most basic six-view trauma ultrasound exam includes the hepatorenal space (\"Morrison's pouch\"), perisplenic space, subcostal space, pelvis, and views of each hemi-thorax (see Videos 2-5; these images are the footprint of a negative FAST). Although abdominal ultrasound views are often unable to isolate the source bleed, such diagnostic information can expedite trauma patients to the operating room for exploratory laparotomy when they are hemodynamically unstable.10-13

The introduction of ultrasound into the standard trauma algorithm work-up has allowed for a more accelerated, definitive surgical approach and, in the right clinical context, a process designed to forgo computed tomography scans.

Although acute coronary syndrome is a \"must not miss\" diagnosis, the initial evaluation of chest pain in the ED includes alternative diagnoses such as aortic dissection, pulmonary embolism, pericardial effusion, and several primary pulmonary processes.14,15 PoCUS can be used to improve diagnostic specificity in such settings. A focused ultrasound of the symptomatic patient with chest pain can address focused questions such as the following: Is there pericardial fluid Is there a discrepancy in right versus left chamber size Are there signs of global cardiac dysfunction Is there an absence of pleural slidingIs the aortic root dilated Or is there a flap seen in the aortic root

Different etiologies of shortness of breath have different sonographic footprints. The presence or absence of the above-mentioned findings on ultrasound aid providers in making quick, often life-saving, clinical decisions at the bedside.

Fortunately, among the numerous pathologies that present as abdominal pain, many are amenable to PoCUS evaluation. Acute renal colic should demonstrate unilateral hydronephrosis and, on occasion, an obstructing stone at the ureterovesicular junction or within the urinary bladder.21 Cholelithiasis is characterized by the presence of rounded, acoustically enhanced structures with distal shadowing artifacts; presence of common bile duct dilatation (diameter >6 mm) indicates biliary obstruction. Acute cholecystitis will show gallbladder wall thickening and pericholecystic fluid.22 An abdominal aortic aneurysm can be identified on ultrasound with a rapid longitudinal evaluation of the abdominal aorta, looking for a diameter measuring >3 cm.23 Finally, an acute intestinal obstruction can be diagnosed by identifying multiple loops of bowel measuring >3 cm in diameter when performing an abdominal sweep (see Video 8). The severity of the obstruction can be further categorized by determining the presence or absence of peristalsis, extra-luminal fluid, bowel wall thickening, and luminal air.24

The POCUS Certification Academy is committed to expanding the knowledge and practical application of point-of-care ultrasound around the world. In partnership with a community of POCUS experts, we offer certifications and educational opportunities that equip professionals to learn and deliver unprecedented patient diagnosis, care, and safety while using point-of-care ultrasound.

Two studies with 80 and 45 participants yielded 100% sensitivity and specificity for AAA screening with POCUS in primary care.4,5 A meta-analysis of seven emergency department POC ultrasound studies demonstrated 99% sensitivity and 98% specificity for AAA diagnosis.6 In another trial, a medical student identified 15 of 16 aneurysms in 57 patients after three hours of training; and the missed aneurysm was an inconclusive study.7 In a large study of primary care AAA screening with 25 hours of physician training, scans were completed in an average of four minutes but showed a 21% false-positive rate; however, misdiagnosed scans showed abnormalities such as aortic ectasia or luminal thrombus.8 Figure 1 shows POCUS scans of a normal abdominal aorta and an abdominal aortic aneurysm.

The bedside lung ultrasound in emergency (BLUE) protocol was developed to categorize findings in acute respiratory distress24,25 (eTable A). In lung ultrasonography, A lines are artifacts running parallel to pleura in healthy lung tissue (Figure 3A), whereas B lines are comet-tail artifacts found perpendicular to pleura from subpleural edema24 (Figure 3B). Ultrasound findings are combined with clinical evaluation; unilateral B lines with fever and cough correlate with pneumonia, and bilateral A lines with wheezing suggest obstructive airway disease given that lung parenchyma is normal in bronchial obstruction.24 POCUS of the lung is more sensitive than plain radiography in diagnosing other conditions, such as pleural effusion (94% sensitivity) and pulmonary contusion (92% sensitivity).26,27 POCUS of the lung decreases emergency department diagnostic time by two hours on average compared with standard radiography, computed tomography (CT), or echocardiography.25

POCUS has been studied to reduce CT imaging in suspected appendicitis. The pooled sensitivity of POCUS for appendicitis is 91% when performed by surgeons and physicians who work in the emergency department.39 A