Pericardial tamponade: A comprehensive emergency medicine and echocardiography review.

INTRODUCTION: Pericardial tamponade requires timely diagnosis and management. It carries a high mortality rate. OBJECTIVE: This review incorporates available evidence to clarify misconceptions regarding the clinical presentation, while providing an in-depth expert guide on bedside echocardiography. It also details the decision-making strategy for emergency management including pericardiocentesis, along with pre- and peri-procedural pearls and pitfalls. DISCUSSION: Pericardial effusions causing tamponade arise from diverse etiologies across acute and sub-acute time courses. The most frequently reported symptom is dyspnea. The classically taught Beck's triad (which includes hypotension) does not appear commonly. Echocardiographic findings include: a pericardial effusion (larger size associated with tamponade), diastolic right ventricular collapse (specific), systolic right atrial collapse (sensitive), a plethoric non-collapsible inferior vena cava (sensitive), and sonographic pulsus paradoxus. Emergent pericardiocentesis is warranted by hemodynamic instability, impending deterioration, or cardiac arrest. Emergent surgical indications include type A aortic dissection causing hemopericardium, ventricular free wall rupture after acute myocardial infarction, severe chest trauma, and iatrogenic hemopericardium when bleeding cannot be controlled percutaneously. Pre-procedure management includes blood products for patients with traumatic hemopericardium; gentle intravenous fluids to hypotensive, hypovolemic patients with consideration for vasoactive medications; treatment of anticoagulation, coagulopathies, and anemia. Positive-pressure ventilation and intravenous sedation can lower cardiac output and should be avoided if possible. Optimal location for echocardiography-guided pericardiocentesis is the largest, shallowest fluid pocket with no intervening vital structures. Patient positioning to prevent hypoxia and liberal amounts of local anesthesia can facilitate patients remaining still. Safe needle guidance and confirmation of catheter placement is achieved using low-depth sonographic views, injection of agitated saline, and evaluation of initial aspirate for hemorrhage. Pericardial fluid should be drained slowly to avoid pericardial decompression syndrome. CONCLUSION: An understanding of the pathophysiology, clinical presentation, echocardiographic findings, and time-sensitive management of pericardial tamponade is essential for emergency physicians.

Thrombotic complications of COVID-19.

INTRODUCTION: The novel coronavirus disease of 2019 (COVID-19) is associated with significant morbidity and mortality. The impact of thrombotic complications has been increasingly recognized as an important component of this disease. OBJECTIVE: This narrative review summarizes the thrombotic complications associated with COVID-19 with an emphasis on information for Emergency Medicine clinicians. DISCUSSION: Thrombotic complications from COVID-19 are believed to be due to a hyperinflammatory response caused by the virus. Several complications have been described in the literature. These include acute limb ischemia, abdominal and thoracic aortic thrombosis, mesenteric ischemia, myocardial infarction, venous thromboembolism, acute cerebrovascular accident, and disseminated intravascular coagulation. CONCLUSION: It is important for Emergency Medicine clinicians to be aware of the thrombotic complications of COVID-19. Knowledge of these components are essential to rapidly recognize and treat to reduce morbidity and mortality in these patients.

Point-of-Care Ultrasonography for the Diagnosis of Skin and Soft Tissue Abscesses: A Systematic Review and Meta-analysis.

STUDY OBJECTIVE: Skin and soft tissue infections are a common chief complaint in the emergency department. Research has shown that clinical examination alone can be unreliable in distinguishing between cellulitis and abscesses, a distinction that is important because they each require different treatments. Point-of-care ultrasonography has been increasingly studied as a tool to improve the diagnostic accuracy for these skin and soft tissue infections. The primary objective of this systematic review is to evaluate the diagnostic accuracy of point-of-care ultrasonography for abscesses. Subgroup analyses are performed for adult versus pediatric patients and high suspicion versus clinically unclear cases. Secondary objectives include the percentage of correct versus incorrect changes in management and reduction in treatment failures because of point-of-care ultrasonography. METHODS: PubMed, Scopus, Latin American and Caribbean Health Sciences Literature database, Cumulative Index of Nursing and Allied Health, Google Scholar, the Cochrane Database of Systematic Reviews, and the Cochrane Central Register of Controlled Trials were assessed from inception to July 26, 2019, for all prospective studies assessing the diagnostic accuracy of point-of-care ultrasonography for evaluation of skin and soft tissue abscesses. Data were dual extracted into a predefined work sheet and quality analysis was performed with the Quality Assessment of Diagnostic Accuracy Studies-2 tool. Diagnostic accuracy was reported as sensitivity, specificity, positive likelihood ratio (LR+), and negative likelihood ratio (LR-), with 95% confidence intervals (CIs). RESULTS: We identified 14 studies comprising 2,656 total patients. Point-of-care ultrasonography was 94.6% sensitive (95% CI 89.4% to 97.4%) and 85.4% specific (95% CI 78.9% to 90.2%), with an LR+ of 6.5 (95% CI 4.4 to 9.6) and LR- of 0.06 (95% CI 0.03 to 0.13). Among cases with a high pretest suspicion for abscess or cellulitis, point-of-care ultrasonography was 93.5% sensitive (95% CI 90.4% to 95.7%) and 89.1% specific (95% CI 78.3% to 94.9%), with an LR+ of 8.6 (95% CI 4.1 to 18.1) and LR- of 0.07 (95% CI 0.05 to 0.12). Among cases that were clinically unclear, point-of-care ultrasonography was 91.9% sensitive (95% CI 77.5% to 97.4%) and 76.9% specific (95% CI 65.3% to 85.5%), with an LR+ of 4.0 (95% CI 2.5 to 6.3) and LR- of 0.11 (95% CI 0.03 to 0.32). Among adults, point-of-care ultrasonography was 98.7% sensitive (95% CI 95.3% to 99.8%) and 91.0% specific (95% CI 84.4% to 95.4%), with an LR+ of 10.9 (95% CI 6.2 to 19.2) and LR- of 0.01 (95% CI 0.001 to 0.06). Among pediatric patients, point-of-care ultrasonography was 89.9% sensitive (95% CI 81.8% to 94.6%) and 79.9% specific (95% CI 71.5% to 86.3%), with an LR+ of 4.5 (95% CI 3.1 to 6.4) and LR- of 0.13 (95% CI 0.07 to 0.23). Point-of-care ultrasonography led to a correct change in management in 10.3% of cases (95% CI 8.9% to 11.8%) and led to an incorrect change in management in 0.7% of cases (95% CI 0.3% to 1.1%). CONCLUSION: According to the current data, point-of-care ultrasonography has good diagnostic accuracy for differentiating abscesses from cellulitis and led to a correct change in management in 10% of cases. Future studies should determine the ideal training and image acquisition protocols.

Does the Addition of M-Mode to B-Mode Ultrasound Increase the Accuracy of Identification of Lung Sliding in Traumatic Pneumothoraces?

OBJECTIVES: It is unknown whether the addition of M-mode to B-mode ultrasound (US) has any effect on the overall accuracy of interpretation of lung sliding in the evaluation of a pneumothorax by emergency physicians. This study aimed to determine what effect, if any, this addition has on US interpretation by emergency physicians of varying training levels. METHODS: One hundred forty emergency physicians were randomized via online software to receive a quiz with B-mode clips alone or B-mode with corresponding M-mode images and asked to identify the presence or absence of lung sliding. RESULTS: The sensitivity, specificity, and accuracy of the diagnosis of lung sliding with and without M-mode US were compared. Overall, the sensitivities, specificities, and accuracies of B-mode + M-mode US versus B-mode US alone were 93.1% and 93.2% (P = .8), 96.0% and 89.8% (P < .0001), and 91.5% and 94.5% (P = .0091), respectively. A subgroup analysis showed that in those providers with fewer than 250 total US scans done previously, M-mode US increased accuracy from 88.2% (95% confidence interval, 86.2%-90.2%) to 94.4% (92.8%-96.0%; P = .001) and increased the specificity from 87.0% (84.5%-89.5%) to 97.2% (95.4%-99.0%; P < .0001) compared with B-mode US alone. There was no statistically significant difference observed in the sensitivity, specificity, and accuracy of B-mode + M-mode US compared with B-mode US alone in those with more than 250 scans. CONCLUSIONS: The addition of M-mode images to B-mode clips aids in the accurate diagnosis of lung sliding by emergency physicians. The subgroup analysis showed that the benefit of M-mode US disappears after emergency physicians have performed more than 250 US examinations.

M.mode.ify: A Free Online Tool to Generate Post Hoc M-Mode Images From Any Ultrasound Clip.

We present a software tool designed to generate an M-mode image post hoc from any B-mode ultrasound clip, along any possible axis. M.mode.ify works by breaking down an ultrasound clip into individual frames. It then rotates and crops these frames by using a user-selected M-mode line. The post hoc M-mode image is created by splicing these frames together. Users can measure time and distance after proper calibration through the M.mode.ify interface. This tool opens up new possibilities for clinical application, quality assurance, and research. It is available free for public use at http://www.ultrasoundoftheweek.com/M.mode.ify/.

The irregular diaphragmatic pleural interface: a novel sonographic sign facilitating the diagnosis of pneumonia.

Pneumonia, a disease that has been reported to be the sixth leading cause of death in the United States, has worsening mortality with delays in diagnosis. As the history and physical examination are excessively inaccurate in the diagnosis of pneumonia, we often rely on chest radiography to rule in or out disease. However, it is found to lack sufficient accuracy when computed tomography is used as the reference standard. Sonography has emerged as a viable alternative to chest radiography in the diagnosis of pneumonia. Here, we describe a novel sonographic sign that can be used to assist in the diagnosis of pneumonia.

Defining an Ultrasound-guided Regional Anesthesia Curriculum for Emergency Medicine.

OBJECTIVES: Ultrasound-guided regional anesthesia (UGRA) can be a powerful tool in the treatment of painful conditions commonly encountered in emergency medicine (EM) practice. UGRA can benefit patients while avoiding the risks of procedural sedation and opioid-based systemic analgesia. Despite these advantages, many EM trainees do not receive focused education in UGRA and there is no published curriculum specifically for EM physicians. The objective of this study was to identify the components of a UGRA curriculum for EM physicians. METHODS: A list of potential curriculum elements was developed through an extensive literature review. An expert panel was convened that included 13 ultrasound faculty members from 12 institutions and from a variety of practice environments and diverse geographical regions. The panel voted on curriculum elements through two rounds of a modified Delphi process. RESULTS: The panelists voted on 178 total elements, 110 background knowledge elements, and 68 individual UGRA techniques. A high level of agreement was achieved for 65 background knowledge elements from the categories: benefits to providers and patients, indications, contraindications, risks, ultrasound skills, procedural skills, sterile technique, local anesthetics, and educational resources. Ten UGRA techniques achieved consensus: interscalene brachial plexus, supraclavicular brachial plexus, radial nerve, median nerve, ulnar nerve, serratus anterior plane, fascia iliaca, femoral nerve, popliteal sciatic nerve, and posterior tibial nerve blocks. CONCLUSIONS: The defined curriculum represents ultrasound expert opinion on a curriculum for training practicing EM physicians. This curriculum can be used to guide the development and implementation of more robust UGRA education for both residents and independent providers.

Early Ambulation After Injury Is Associated With Increased Muscle Size and Strength.

BACKGROUND: Trauma and management of injuries can result in reduction or loss of mobility, which can lead to skeletal muscle deconditioning and sustained disability. Prior investigators have examined changes in skeletal muscle due to injury and immobility separately. The muscular consequences of combined immobility and trauma have not been systematically investigated. OBJECTIVE: The purpose of this study was to explore the association of time to first ambulation with skeletal muscle size and strength in patients after major trauma. METHODS: Adults (N = 19) admitted for major trauma (Injury Severity Score [ISS] > 15) provided daily measures of muscle size (ultrasound) and strength (dynamometry) during hospitalization. Participants were grouped based on time to first ambulation. Repeated measures analysis of variance was used to compare muscle measures between the groups across 5 days while controlling for age and gender. RESULTS: Participants were primarily male (63%) aged 40 ± 17 years with a mean ISS of 21 ± 4. Early ambulation was associated with a 10% increase from baseline in bicep size on Days 3 and 4 and a 15% increase from baseline on Day 5. There were no changes in rectus femoris size in either group. The early ambulation group was significantly stronger than the delayed ambulation group throughout the study in measures taken with the biceps (22%-37%) and quadriceps (26%-46%). CONCLUSION: Early ambulation following major trauma was associated with increased bicep size and greater muscle strength in the biceps and quadriceps muscles over time.

Use of echocardiography to identify appropriate placement of a central venous catheter wire in the vena cava prior to cannulation.

Ultrasound guidance is now the standard of care when placing a central venous catheter (CVC), resulting in decreased complications and increased first-pass success rates. However, even with ultrasound guidance being used for the initial venipuncture, misplacement of a CVC in either an unwanted vein or in an artery still occurs. Here, we discuss a simple technique to assist in the adequate placement of the CVC in the vena cava using bedside echocardiography.