Left Ventricular Ejection Fraction Assessment by Emergency Physician-Performed Bedside Echocardiography: A Prospective Comparative Evaluation of Multiple Modalities.

BACKGROUND: Although there is some support for visual estimation (VE) as an accurate method to estimate left ventricular ejection fraction (LVEF), it is also scrutinized for its subjectivity. Therefore, more objective assessments, such as fractional shortening (FS) or e-point septal separation (EPSS), may be useful in estimating LVEF among patients in the emergency department (ED). OBJECTIVE: Our aim was to compare the real-world accuracy of VE, FS, and EPSS using a sample of point-of-care cardiac ultrasound transthoracic echocardiography (POC-TTE) images acquired by emergency physicians (EPs) with the gold standard of Simpson's method of discs, as measured by comprehensive cardiology-performed echocardiography. METHODS: We conducted a single-site prospective observational study comparing VE, FS, and EPSS to assess LVEF. Adult patients in the ED receiving both POC-TTE and comprehensive cardiology TTE were included. EPs acquired POC-TTE images and videos that were then interpreted by 2 blinded EPs who were fellowship-trained in emergency ultrasound. EPs estimated LVEF using VE, FS, and EPSS. The primary outcome was accuracy. RESULTS: Between April and May 2018, 125 patients were enrolled and 113 were included in the final analysis. EP1 and EP2 had a κ of 0.94 (95% confidence interval [CI] 0.87-1.00) and 0.97 (95% CI 0.91-1.00), respectively, for VE compared with gold standard, a κ of 0.40 (95% CI 0.23-0.57) and 0.38 (95% CI 0.18-0.57), respectively, for EPSS compared with gold standard, and a κ of 0.70 (95% CI 0.54-0.85) and 0.66 (95% CI 0.50-0.81), respectively, for FS compared with gold standard. Sensitivity of severe dysfunction was moderate to high in VE (EP1 85% and EP2 93%), poor to moderate in FS (EP1 73% and EP2 50%), and poor in EPSS (EP1 11% and EP2 18%). CONCLUSIONS: Using a real-world sample of POC-TTE images, the quantitative measurements of EPSS and FS demonstrated poor accuracy in estimating LVEF, even among experienced sonographers. These methods should not be used to determine cardiac function in the ED. VE by experienced physicians demonstrated reliable accuracy for estimating LVEF compared with the gold standard of cardiology-performed TTE.

Standard long IV catheters versus extended dwell catheters: A randomized comparison of ultrasound-guided catheter survival.

INTRODUCTION: Establishing peripheral intravenous (IV) access is a vital step in providing emergency care. Ten to 30% of Emergency Department (ED) patients have difficult vascular access (DVA). Even after cannulation, early failure of US-guided IV catheters is a common complication. The primary goal of this study was to compare survival of a standard long IV catheter to a longer extended dwell catheter. METHODS: This study was a prospective, randomized comparative evaluation of catheter longevity. Two catheters were used in the comparison: [1] a standard long IV catheter, the 4.78 cm 20 gauge Becton Dickinson (BD); and [2] a 6 cm 3 French (19.5 gauge) Access Scientific POWERWAND™ extended dwell catheter (EDC). Adult DVA patients in the ED with vein depths of 1.20 cm-1.60 cm and expected hospital admissions of at least 24 h were recruited. RESULTS: 120 patients were enrolled. Ultimately, 70 patients were included in the survival analysis, with 33 patients in the EDC group and 37 patients in the standard long IV group. EDC catheters had lower rates of failure (p = 0.0016). Time to median catheter survival was 4.04 days for EDC catheters versus 1.25 days for the standard long IV catheter. Multivariate survival analysis also showed a significant survival benefit for the EDC catheter (p = 0.0360). CONCLUSION: A longer extended dwell catheter represents a viable and favorable alternative to the standard longer IVs used for US-guided cannulation of veins >1.20 cm in depth. These catheters have significantly improved survival rates with similar insertion success characteristics.

Ultrasound-guided intravenous catheter survival impacted by amount of catheter residing in the vein.

OBJECTIVE: Ultrasound (US)-guided peripheral IVs have a high failure rate. We explore the relationship between the quantity of catheter residing within the vein and the functionality of the catheter over time. METHODS: This was a prospective, observational single-site study. Adult ED patients with US-guided IVs had the catheter visualised under ultrasound post-placement. IV placement time and catheter length residing in the vein was obtained. Exclusions included catheter not visualised, patient discharged from ED unless IV failed, <24 hour hospitalisation unless IV failed or patient self-removed IV.Inpatient follow-up occurred within 24, 48 and 72 hours from the IV placement time. Catheter functionality was noted. If the catheter failed, the time and reason for failure was documented. RESULTS: 113 patients were enrolled; 27 were excluded. Of the 86 study subjects, 29 (33.7%) patients' IVs failed and 57 (66.3%) remained functional. Median time to IV failure was 15.6 hours. 100% of IVs failed when <30% of the catheter was in the vein; 32.4% of IVs failed when 30%-64% of the catheter was in the vein; no IVs failed when ≥65% of the catheter was in the vein (p<0.0002). The HR was 0.71 (95% CI 0.60 to 0.83), and for every 5% increase of catheter in vein, the hazard of the IV failing decreases by 29% (p<0.0001). CONCLUSION: The quantity of catheter residing in the vein is a key predictor of long-term functionality of US-guided IVs and is strongly associated with the hazard of failure within 72 hours. Catheter failure is high when <30% of the catheter resided in the vein. Optimum catheter survival occurs when ≥65% of the catheter is placed in the vein.

Inferior vena cava assessment in the bedside diagnosis of acute heart failure.

OBJECTIVES: The objective of this study was to determine the test characteristics of the caval index and caval-aortic ratio in predicting the diagnosis of acute heart failure in patients with undifferentiated dyspnea in the emergency department (ED). METHODS: This prospective observational study was performed at an urban ED that enrolled patients, 50 years or older, with acute dyspnea. A sonographic caval index was calculated as the percentage decrease in the inferior vena cava (IVC) diameter during respiration. A caval-aortic ratio was defined by the maximum IVC diameter divided by the aortic diameter. The sensitivity, specificity, and likelihood ratios of these measurements associated with heart failure were estimated. RESULTS: Eighty-nine patients were enrolled in the study with a mean age of 68 years. A caval index of less than 33% had 80% sensitivity (95% confidence interval [CI], 63%-91%) and 81% specificity (95% CI, 68%-90%) in diagnosing acute heart failure, whereas an index of less than 15% had a 37% sensitivity (95% CI, 22%-55%) and 96% specificity (95% CI, 86%-99%). The sensitivity of a caval-aortic ratio of more than 1.2 was 33% (95% CI, 18%-52%) and the specificity was 96% (95% CI, 86%-99%). Positive likelihood ratios were 10 for a caval index of less than 15%, 4.3 for an index of less than 33%, and 8.3 for a caval-aortic ratio of more than 1.2. CONCLUSION: Bedside assessments of the caval index or caval-aortic ratio may be useful clinical adjuncts in establishing the diagnosis of acute heart failure in patients with undifferentiated dyspnea.

Ultrasound in Medical Education: Can Students Teach Themselves?

INTRODUCTION: A new technology in medical education is ultrasound simulation, which has been shown to help students learn while reducing load on clinical instructors. The goal of this study is to compare the efficacy of teaching using ultrasound simulators versus more traditional instructor-led sessions with ultrasound machines. METHODS: Ultrasound was used to teach cardiac anatomy and physiology to medical students. Volunteers in one group were instructed using an ultrasound simulator (SonoSim) with built-in lessons; the other group received a traditional instructor-led session with an ultrasound machine. Efficacy of each type of teaching was assessed by measuring improvement from a pre-session test to a post-session test, using a one-sample paired t-test to compare averages between groups. Participants were given a survey to solicit opinions of the lessons. RESULTS: Twenty-one medical students participated, with 12 in the instructor-led group and 9 in the simulator group. Both groups increased their test scores from pre-session to post-session; the average increase was 5% in the instructor-led and 10% in the simulator group (p = 0.437). There was no statistically significant difference between groups in how effective or enjoyable the lesson felt. Participants from either group who tried both methods were likely to prefer the traditional ultrasound teaching. CONCLUSION: Self-guided learning with simulators and traditional instructor-led lectures are both effective for teaching basic cardiac anatomy and physiology via ultrasound. However, most students prefer learning with instructors if given the opportunity. Self-guided ultrasound simulators may serve as an effective standalone learning method or an adjunct to instructor-led sessions.

Comparison of Ultrasound and Plain Radiography for the Detection of Long-bone Fractures.

OBJECTIVE: To compare emergency medicine (EM) resident physicians' ability to identify long-bone fractures using ultrasound (US) versus plain radiography (X-ray). METHODS: This was an IRB-approved, randomized prospective study. Study participants included 40 EM residents at a single site. Fractures were mechanically induced in five chicken legs, and five legs were left unfractured. Chicken legs were imaged by both modalities. Participants were given 2 min to view each of the images. Participants were randomized to either US or X-ray interpretation first and randomized to viewing order within each arm. Participants documented the presence or absence of fracture and location and type of fracture when pertinent. Mean proportions and standard deviations (SDs) were analyzed using paired t-test and linear models. RESULTS: Forty residents (15 postgraduate years (PGY)-1, 12 PGY-2, 13 PGY-3) participated in the study. Thirty-one participants were male, and 19 were randomized to US first. Residents completed a mean of 185 (SD 95.8) US scans before the study in a variety of applications. Accurate fracture identification had a higher mean proportion in the US arm than the X-ray arm, 0.89 (SD 0.11) versus 0.75 (SD 0.11), respectively (P < 0.001). There was no statistically significant difference in US arm and X-ray arm for endpoints of fracture location and type. CONCLUSION: EM residents were better able to identify fractures using US compared to X-ray, especially as level of US and ED experience increased. These results encourage the use of US for the assessment of isolated extremity injury, particularly when the injury is diaphyseal.

Acute Portal Vein Thrombosis Diagnosed with Point-of-care Ultrasonography.

Abdominal pain is the most common presenting complaint to the emergency department (ED);1 however, acute portal vein thrombosis is an uncommon cause of abdominal pain. In the following case report, we present a patient who presented to the ED with symptoms of gastroenteritis but was ultimately diagnosed with acute portal vein thrombosis by point-of-care ultrasound (POCUS).