Chandra Aubin

Ultrasonography versus Computed Tomography for Suspected Nephrolithiasis

BACKGROUND There is a lack of consensus about whether the initial imaging method for patients with suspected nephrolithiasis should be computed tomography (CT) or ultrasonography. METHODS In this multicenter, pragmatic, comparative effectiveness trial, we randomly assigned patients 18 to 76 years of age who presented to the emergency department with suspected nephrolithiasis to undergo initial diagnostic ultrasonography performed by an emergency physician (point-of-care ultrasonography), ultrasonography performed by a radiologist (radiology ultrasonography), or abdominal CT. Subsequent management, including additional imaging, was at the discretion of the physician. We compared the three groups with respect to the 30-day incidence of high-risk diagnoses with complications that could be related to missed or delayed diagnosis and the 6-month cumulative radiation exposure. Secondary outcomes were serious adverse events, related serious adverse events (deemed attributable to study participation), pain (assessed on an 11-point visual-analogue scale, with higher scores indicating more severe pain), return emergency department visits, hospitalizations, and diagnostic accuracy. RESULTS A total of 2759 patients underwent randomization: 908 to point-of-care ultrasonography, 893 to radiology ultrasonography, and 958 to CT. The incidence of high-risk diagnoses with complications in the first 30 days was low (0.4%) and did not vary according to imaging method. The mean 6-month cumulative radiation exposure was significantly lower in the ultrasonography groups than in the CT group (P<0.001). Serious adverse events occurred in 12.4% of the patients assigned to point-of-care ultrasonography, 10.8% of those assigned to radiology ultrasonography, and 11.2% of those assigned to CT (P=0.50). Related adverse events were infrequent (incidence, 0.4%) and similar across groups. By 7 days, the average pain score was 2.0 in each group (P=0.84). Return emergency department visits, hospitalizations, and diagnostic accuracy did not differ significantly among the groups. CONCLUSIONS Initial ultrasonography was associated with lower cumulative radiation exposure than initial CT, without significant differences in high-risk diagnoses with complications, serious adverse events, pain scores, return emergency department visits, or hospitalizations. (Funded by the Agency for Healthcare Research and Quality.).

Residents Should Not Independently Perform Focused Abdominal Sonography for Trauma After 10 Training Examinations

Objectives. To assess whether 10 focused abdominal sonography for trauma (FAST) examinations could be used as a minimum standard for training, as suggested previously. Methods. This was a retrospective review of patients with abdominal trauma who underwent resident‐performed FAST examinations before surgical or Department of Radiology evaluation. Results. Six hundred ninety‐eight patients were examined by resident‐performed FAST followed by reference standard evaluations. Four hundred twelve patients were evaluated by residents who previously performed 10 FAST examinations; 154 were evaluated by 29 residents performing their 11th through 30th examinations; and 258 were evaluated by 10 residents performing their 31st and subsequent examinations. The results of resident‐performed FAST for intraperitoneal free fluid were as follows: 11 to 20 examinations—sensitivity, 73.9% (95% confidence interval, 51.3%–88.9%); specificity, 98.8% (92.5%–99.9%); true‐positive findings, 17; true‐negative, 81; false‐positive, 1; false‐negative, 6; total patients, 105; 21 to 30 examinations—sensitivity, 100% (73.2%–100%); specificity, 97.1% (83.3%–99.9%); true‐positive, 14; true‐negative, 34; false‐positive, 1; false‐negative, 0; total patients, 49; 31 and more examinations—sensitivity, 94.8% (88.6%–97.9%); specificity, 98.6% (94.5%–99.8%); true‐positive, 110; true‐negative, 140; false‐positive, 2; false‐negative, 6; total patients, 258. Conclusions. The suggestion that 10 examinations could be used as a minimum standard for training in FAST examinations was not validated.

Ventricular fibrillation in a man shot with a Taser

Controversy exists concerning the lethality of Tasers. These are conducted electrical weapons which incapacitate subjects by delivering an electrical charge that causes diffuse muscle contraction. In North America, over 440 deaths have been reported immediately following Taser use. Taser International has recently suggested that Tasers should not be aimed at the chest, although there is no conclusive proof that a discharge over the heart would cause an arrhythmia. The case history is presented of a young man who was shot in the chest by a Taser and presented to the emergency department in ventricular fibrillation.

The Technical Errors of Physicians Learning to Perform Focused Assessment With Sonography in Trauma

OBJECTIVES The objective was to assess the incidence of various technical errors committed by emergency physicians (EPs) learning to perform focused assessment with sonography in trauma (FAST). METHODS This was a retrospective review of the first 75 consecutive FAST exams for each EP from April 2000 to June 2005. Exams were assessed for noninterpretable views, misinterpretation of images, poor gain, suboptimal depth, an incomplete exam, or backward image orientation. RESULTS A total of 2,223 FAST exams done by 85 EPs were reviewed. Multiple noninterpretable views or misinterpreted images occurred in 24% of exams for those performing their first 10 exams, 3.6% for those performing their 41st to 50th exams, and 0% for those performing their 71st to 75th exams (Cochran-Armitage trend test = 10.5, p < 0.0001). A single noninterpretable view, poor gain, suboptimal depth, incomplete exam, or backward image orientation occurred in 48% of exams for those performing their first 10 exams, 17% for those performing their 41st to 50th exams, and 5% for those performing their 71st to 75th exams (Cochran-Armitage trend test = 11.6, p < 0.0001). CONCLUSIONS The incidence of specific technical errors of EPs learning to perform FAST at our institution improved with hands-on experience. Interpretive skills improved more rapidly than image acquisition skills.

Jugular venous distension on ultrasound: sensitivity and specificity for heart failure in patients with dyspnea

BACKGROUND Accurately diagnosing congestive heart failure (CHF) in patients with dyspnea can be difficult because clinical history and physical examination are often nondiagnostic and may be inaccurate, especially when patients have complicated comorbid conditions. OBJECTIVE To prospectively assess jugular venous distension on ultrasound (JVD-US) performed by emergency physicians for identifying CHF on echocardiography by the department of cardiology (C-ECHO) in patients with dyspnea. MEASUREMENTS This was a secondary analysis of a previously collected data set from a prospective study of JVD-US in ED patients with dyspnea due to suspected CHF. C-ECHO results were obtained and used as the criterion standard. RESULTS Jugular venous distension on ultrasound had a sensitivity of 99% (95% confidence interval [CI], 92.2%-100%), specificity of 59% (95% CI, 40.9%-74.4%), positive likelihood ratio of 2.4 (95% CI, 1.6-3.6), and negative likelihood ratio of 0.01 (95% CI, 0.0007-0.20) for identifying CHF on C-ECHO in patients with dyspnea. CONCLUSION This initial study suggests that JVD-US by emergency physicians is predictive of CHF using echocardiography performed by the department of cardiology as the criterion standard.

The predictive value of physical examination findings in patients with suspected acute heart failure syndrome

It can be difficult to differentiate acute heart failure syndrome (AHFS) from other causes of acute dyspnea, especially when patients present in extremis. The objective of the study was to determine the predictive value of physical examination findings for pulmonary edema and elevated B-type natriuretic peptide (BNP) levels in patients with suspected AHFS. This was a secondary analysis of a previously reported prospective study of jugular vein ultrasonography in patients with suspected AHFS. Charts were reviewed for physical examination findings, which were then compared to pulmonary edema on chest radiography (CXR) read by radiologists blinded to clinical information and BNP levels measured at presentation. The predictive value of every sign and combination of signs for pulmonary edema on CXR or an elevated BNP was poor. Since physical examination findings alone are not predictive of pulmonary edema or an elevated BNP, clinicians should have a low threshold for using CXR or BNP in clinical evaluation. This brief research report suggests that no physical examination finding or constellation of findings can be used to reliably predict pulmonary edema or an elevated BNP in patients with suspected AHFS.

Jugular vein ultrasound and pulmonary oedema in patients with suspected congestive heart failure.

Background The diagnosis of patients with acute dyspnoea is challenging, as clinical history and physical examination are often nondiagnostic and inaccurate. Consequently, clinicians often rely on the results of chest radiography (CXR) to determine the initial intervention and guide further treatment. Objective The purpose of this study was to prospectively assess the sensitivity and specificity of ultrasonographic assessment of jugular venous distension (US-JVD) for identifying pulmonary oedema on CXR in dyspnoeic patients with suspected congestive heart failure. Measurements US-JVD was compared with initial CXR findings of pulmonary oedema as determined by radiology consultants blinded to all clinical information and US-JVD measurements. Results US-JVD had a sensitivity of 98.2% [95% confidence interval (CI), 89.2–99.9] and a specificity of 42.9% (95% CI, 30.7–55.9), a likelihood ratio positive of 1.7 (95% CI, 1.4–2.1), and likelihood ratio negative of 0.04 (95% CI, 0.006–0.3), for identifying dyspnoeic patients with pulmonary oedema on initial CXR. Conclusion US-JVD is a sensitive test for identifying pulmonary oedema on CXR in dyspnoeic patients with suspected congestive heart failure.

Sonographic assessment of jugular venous distension and B-type natriuretic peptide levels in patients with dyspnoea

Background Sonographic assessment of jugular venous distension (US-JVD) has been described as a sensitive test for pulmonary oedema on chest x-ray in patients with dyspnoea, but chest x-ray may not detect all patients with raised B-type natriuretic peptide (BNP) levels. Objective To compare US-JVD and initial BNP levels in patients with dyspnoea. Methods This was a secondary analysis of a previously collected dataset from a prospective study of US-JVD in patients with dyspnoea due to suspected congestive cardiac failure. Initial BNP levels were obtained for each patient. The sensitivity, specificity, positive and negative predictive values (PPV and NPV), and likelihood ratios (LR) of US-JVD ≥8 cm H2O for BNP ≥500 pg/ml were calculated. The product moment correlation coefficient between US-JVD and BNP was also calculated. Results 119 patients were included in the initial study. US-JVD ≥8 cm H2O had a sensitivity of 100% (95% CI 92% to 100%), specificity of 43% (95% CI 31% to 56%), PPV of 61% (95% CI 50% to 71%), NPV of 100% (95% CI 84% to 100%), LR+=1.75 (95% CI 1.41 to 2.17), and LR−=0 for a BNP ≥ 500 pg/ml. The Pearson correlation coefficient between US-JVD and BNP was 0.35 (95% CI 0.18 to 0.50) and the Spearman correlation coefficient was 0.73 (95% CI 0.63 to 0.80), suggesting a monotonic, but non-linear relationship between US-JVD and BNP. Conclusion US-JVD correlates with initial BNP levels and is a sensitive test for raised BNP levels in patients with dyspnoea due to suspected congestive cardiac failure.