Diagnosing heart failure among acutely dyspneic patients with cardiac, inferior vena cava, and lung ultrasonography.

BACKGROUND: Rapid diagnosis (dx) of acutely decompensated heart failure (ADHF) may be challenging in the emergency department (ED). Point-of-care ultrasonography (US) allows rapid determination of cardiac function, intravascular volume status, and presence of pulmonary edema. We test the diagnostic test characteristics of these 3 parameters in making the dx of ADHF among acutely dyspneic patients in the ED. METHODS: This was a prospective observational cohort study at an urban academic ED. Inclusion criteria were as follows: dyspneic patients, at least 18 years old and able to consent, whose differential dx included ADHF. Ultrasonography performed by emergency sonologists evaluated the heart for left ventricular ejection fraction (LVEF), the inferior vena cava for collapsibility index (IVC-CI), and the pleura sampled in each of 8 thoracic regions for presence of B-lines. Cutoff values for ADHF were LVEF less than 45%, IVC-CI less than 20%, and at least 10 B-lines. The US findings were compared with the final dx determined by 2 emergency physicians blinded to the US results. RESULTS: One hundred one participants were enrolled: 52% male, median age 62 (25%-75% interquartile, 53-91). Forty-four (44%) had a final dx of ADHF. Sensitivity and specificity (including 95% confidence interval) for the presence of ADHF were as follows: 74 (65-90) and 74 (62-85) using LVEF less than 45%, 52 (38-67) and 86 (77-95) using IVC-CI less than 20%, and 70 (52-80) and 75 (64-87) using B-lines at least 10. Using all 3 modalities together, the sensitivity and specificity were 36 (22-51) and 100 (95-100). As a comparison, the sensitivity and specificity of brain natriuretic peptide greater than 500 were 75 (55-89) and 83 (67-92). CONCLUSION: In this study, US was 100% specific for the dx of ADHF.

Inter-rater reliability of quantifying pleural B-lines using multiple counting methods.

OBJECTIVES: Sonographic B-lines are a sign of increased extravascular lung water. Several techniques for quantifying B-lines within individual rib spaces have been described, as well as different methods for "scoring" the cumulative B-line counts over the entire thorax. The interobserver reliability of these methods is unknown. This study examined 3 methods of quantifying B-lines for inter-rater reliability. METHODS: Videotaped pleural assessments of adult patients presenting to the emergency department with dyspnea and suspected acute heart failure were reviewed by 3 blinded pairs of emergency physicians. Each pair performed B-line counts within single rib spaces using 1 of the following 3 predetermined methods: 1, individual B-lines are counted over an entire respiratory cycle; 2, as per method 1, but confluent B-lines are counted as multiple based on the percentage of the rib space they occupy; and 3, as per method 2, but the count is made at the moment when the most B-lines are seen, not over an entire respiratory cycle. A single-measures interclass correlation coefficient was used to assess inter-rater reliability for the 3 definitions of B-line counts. RESULTS: A total of 456 video clips were reviewed. The interclass correlation coefficients (95% confidence intervals) for methods 1, 2, and 3 were 0.84 (0.81-0.87), 0.87 (0.85-0.90), and 0.89 (0.87-0.91), respectively. The difference between methods 1 and 3 was significant (P = .003). CONCLUSIONS: All methods of B-line quantification showed substantial inter-rater agreement. Method 3 is more reliable than method 1. There were no other significant differences between the methods. We recommend the use of method 3 because it is technically simpler to perform and more reliable than method 1.

Diagnosis of a facial artery pseudoaneurysm using emergency bedside ultrasound.

BACKGROUND: Pseudoaneurysms of the extracranial arterial system are rare. We report a case of a facial artery pseudoaneurysm initially mistaken for an abscess. With bedside ultrasound performed in the Emergency Department (ED) by the treating physician, the mass was identified as a pseudoaneurysm. OBJECTIVES: In this report we review the anatomy of the extracranial arterial system of the head and neck, discuss the pathogenesis and clinical presentation of pseudoaneuryms, and present diagnostic imaging and treatment options for pseudoaneurysms of the face. CASE REPORT: A 51-year-old man presented with facial swelling and pain at the site of a laceration that he had sustained 1 month previously. Before incision and drainage, bedside ultrasound was performed in the ED by the treating physician to confirm the presumptive diagnosis of abscess with possible foreign body. The ultrasound revealed the mass to be a pseudoaneurysm. CONCLUSIONS: Although pseudoaneurysms of the head and neck are rare, a history of trauma should prompt the consideration of a vascular injury with the need for imaging before drainage procedures of a presumed abscess. To our knowledge, the use of clinician-performed bedside ultrasound to detect facial artery pseudoaneurysms has never been reported.

The interrater reliability of inferior vena cava ultrasound by bedside clinician sonographers in emergency department patients.

OBJECTIVES: Inferior vena cava ultrasound (IVC-US) is a noninvasive bedside tool to assess intravascular volume status. This study set out to investigate the interrater reliability of IVC-US by bedside clinician sonographers and determine whether alternative methods of IVC-US such as B-mode and visual estimation are equally reliable to traditional M-mode. METHODS: A convenience sample of adult emergency department (ED) patients was prospectively enrolled. Each patient underwent IVC-US by two different emergency physicians (EPs), each of whom first performed visual estimation of IVC percent collapse and of volume status, followed by caliper measurements in M-mode and B-mode. EPs were blinded to patient data and to the other sonographer's results. For each technique, interrater reliability was determined between the two EPs' assessments using intraclass correlation coefficients (ICC) for continuous data and Cohen's weighted kappa for categorical data. In addition, analysis was performed on M-mode diameter measurements to determine the relationship between sonographer and patient characteristics on interrater reliability. RESULTS: Five EPs performed 92 US exams on 46 patients. Using M-mode, the ICC for maximum IVC diameter was 0.81 (95% confidence interval [CI]=0.67 to 0.89), and for minimum diameter was 0.77 (95% CI=0.62 to 0.87). There were no statistically significant differences between the caliper methods used for IVC measurements (M-mode diameter, B-mode diameter, or B-mode area). Agreement for visually estimated IVC collapse (0.60, 95% CI=0.36 to 0.76) was similar to agreement for calculated M-mode IVC collapse index (0.52, 95% CI=0.27 to 0.71). Cohen's weighted kappa for volume status based on visual estimation of IVC filling (size, shape, and collapse) was 0.64 (95% CI=0.53 to 0.73). ICC values for M-mode diameter measurements were significantly higher in studies involving patients who were noneuvolemic and studies in which sonographers had each performed at least five prior IVC-US. CONCLUSIONS: Emergency physicians' US measurements of IVC diameter have a high degree of interrater reliability. IVC percent collapse by visual estimation or based on caliper measurements have lower, but still moderate to good reliability. The use of the visual estimation technique should be considered by clinicians who have learned to obtain measured parameters of IVC filling because it is equally reliable to traditional M-mode and can be performed more rapidly.