Echocardiographic diagnosis and clinical implications of wide-open tricuspid regurgitation for evaluating right ventricular dysfunction in the emergency department.

The tricuspid regurgitation pressure gradient (TRPG) reflects the difference in pressure between the right ventricle and right atrium (ΔPRV-RA). Its estimation by echocardiography correlates well with that obtained using right-heart catheterization. An elevated TRPG is an important marker for identifying right ventricular dysfunction in both the acute and chronic settings. However, in the "wide-open" variant of TR, the TRPG counterintuitively falls. Failure to recognize this potential pitfall and underlying pathophysiology can cause underestimation of the severity of right ventricular dysfunction. This could lead to erroneous fluid tolerance assessments, and potentially harmful resuscitative and airway management strategies. In this manuscript, we illustrate the pathophysiology and potential pitfall of wide-open TR through a series of cases in which emergency physicians made the diagnosis using cardiac point-of-care ultrasound. To our knowledge, this clinical series is the first to demonstrate recognition of the paradoxically-low TRPG of wide-open TR, which guided appropriate management of critically ill patients in the emergency department.

Is pulmonary hypertension protective against cardiac tamponade? A systematic review.

The presence of pulmonary hypertension (PH) may affect whether cardiac tamponade physiology develops from a pericardial effusion. Specifically, the increased intracardiac pressure and right ventricular hypertrophy associated with PH would seemingly increase the intrapericardial pressure threshold at which the right-sided chambers collapse. In this systematic review, we examined the impact of PH on the incidence, in-hospital and long-term mortality, and echocardiographic findings of patients with cardiac tamponade. Using the PRISMA guideline, a systematic search was conducted in PubMed, Academic Search Premier, Web of Science, Google Scholar, and the Cochrane Database for studies investigating PH and cardiac tamponade. The Newcastle-Ottawa Scale was used to analyze the quality of returned studies. Primary outcomes included the incidence of cardiac tamponade, as well as in-hospital and long-term mortality rates. Secondary outcomes were the presence or absence of echocardiographic findings of cardiac tamponade in patients with PH. Forty-three studies (9 cohort studies and 34 case reports) with 1054 patients were included. The incidence of cardiac tamponade was significantly higher in patients with PH compared to those without PH, 2.0% (95% CI 1.2-3.2%) vs. 0.05% (95% CI 0.05-0.05%), p < 0.0001, OR 40.76 (95% CI 24.8-66.9). The incidence of tamponade in patients with a known pericardial effusion was similar in those with and without PH, 20.3% (95% CI 12.0-32.3%) and 20.9% (95% CI 18.0-24.1%), p = 0.9267, OR 0.97 (95% CI 0.50-1.87). In patients with tamponade, those with PH demonstrated a significantly higher in-hospital mortality than those without PH, 38.8% (95% CI 26.4-52.8%) vs. 14.4% (95% CI 14.2-14.6%), p < 0.0001, OR 3.77 (95% CI 2.12-6.70). Long-term mortality in patients with tamponade was significantly lower in those with PH than in those without PH, 45.5% (95% CI 33.0-58.5%) vs. 59.1% (95% CI 54.7-63.4%), p = 0.0258, OR 0.576 (95% CI 0.33-1.01). However, after stratifying by non-malignant etiologies, the long-term mortality benefit for those with PH disappeared. In the studies that described specific echocardiographic findings of cardiac tamponade, only 10.5% of patients with PH and tamponade showed right atrial and right ventricular collapse. When evaluating patients with pericardial effusions, physicians must recognize the effects of underlying PH on the incidence, in-hospital and long-term mortality rates, and potentially atypical echocardiographic presentation of cardiac tamponade.

What echocardiographic findings differentiate acute pulmonary embolism and chronic pulmonary hypertension?

BACKGROUND: Pulmonary embolism (PE) and pulmonary hypertension (PH) are potentially fatal disease states. Early diagnosis and goal-directed management improve outcomes and survival. Both conditions share several echocardiographic findings of right ventricular dysfunction. This can inadvertently lead to incorrect diagnosis, inappropriate and potentially harmful management, and delay in time-sensitive therapies. Fortunately, bedside echocardiography imparts a few critical distinctions. OBJECTIVE: This narrative review describes eight physiologically interdependent echocardiographic parameters that help distinguish acute PE and chronic PH. The manuscript details each finding along with associated pathophysiology and summarization of the literature evaluating diagnostic utility. This guide then provides pearls and pitfalls with high-quality media for the bedside evaluation. DISCUSSION: The echocardiographic parameters suggesting acute or chronic right ventricular dysfunction (best used in combination) are: 1. Right heart thrombus (acute PE) 2. Right ventricular free wall thickness (acute ≤ 5 mm, chronic > 5 mm) 3. Tricuspid regurgitation pressure gradient (acute ≤ 46 mmHg, chronic > 46 mmHg, corresponding to tricuspid regurgitation maximal velocity ≤ 3.4 m/sec and > 3.4 m/sec, respectively) 4. Pulmonary artery acceleration time (acute ≤ 60-80 msec, chronic < 105 msec) 5. 60/60 sign (acute) 6. Pulmonary artery early-systolic notching (proximally-located, higher-risk PE) 7. McConnell's sign (acute) 8. Right atrial enlargement (equal to left atrial size suggests acute, greater than left atrial size suggests chronic). CONCLUSIONS: Emergency physicians must appreciate the echocardiographic findings and associated pathophysiology that help distinguish acute and chronic right ventricular dysfunction. In the proper clinical context, these findings can point towards PE or PH, thereby leading to earlier goal-directed management.

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.

Teaching Module on Ultrasound-Guided Venous Access Using a Homemade Gel Model for Fourth-Year Medical Students.

INTRODUCTION: Evidence supports an ultrasound-guided approach in patients with difficult vascular access. Prior research on teaching ultrasound-guided intravenous access has included only small groups of first- and second-year medical students. METHODS: We enrolled fourth-year medical students in our teaching module. The module featured a 6-minute prelearning narrated lecture and 5-minute orientation, followed by ultrasound-guided IV placement on homemade gel models. Facilitators were emergency medicine (EM) residents with a prespecified level of procedural ultrasound skills according to EM milestones. Students completed pre- and postmodule surveys. Facilitators completed the Directly Observed Procedural Skills Evaluation. Primary outcomes included global rating, proficiency on six procedural skills, and perceived learning. RESULTS: Our module was completed by 150 fourth-year medical students (94% of the class); 84% cannulated the vein in one attempt. We used a global rating scale to describe the students' cannulation abilities; 59% were trusted to perform this procedure with direct supervision and coaching, 29% with indirect supervision, and 8% without supervision. There was no association between a student's order of attempting IV access within the group and global rating (p = .41). Students reported increased understanding of indications, antecubital anatomy, sonographic anatomy, and procedural comfort (12%, 29%, 38%, and 65% improvement pre- vs. postmodule, respectively; p < .001). DISCUSSION: Our module enabled more than one-third of fourth-year medical students to achieve an indirect supervision or better level of proficiency in ultrasound-guided IV access, with significant improvements in perceived knowledge. This module may be useful for other educators facilitating the transition to residency.