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.).

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.

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 H(2)O 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 H(2)O 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.

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 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.

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.

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.

Operator confidence correlates with more accurate abdominal ultrasounds by emergency medicine residents.

The purpose of this study was to assess whether greater operator confidence correlates with more accurate focused abdominal ultrasounds (FAUS) by residents. This was a prospective study of novice residents performing FAUS in patients with abdominal pain. FAUS included focused assessment with sonography for trauma, gall bladder, renal, and aortic examinations. Residents answered the question, "How confident are you of your findings?" using a visual scale from 1 (doubtful) to 5 (certain). The results of the resident-performed FAUS were compared to subsequent criterion evaluations. Thirty-eight residents with an average experience of 27 (95% confidence interval [CI] 18-36) prior US examinations evaluated 504 patients. Greater operator confidence correlated with improved accuracy of FAUS (R(2) = 0.858, p = 0.0369). Sensitivity and specificity were 14% (95% CI 4-37 %) and 71% (95% CI 48-88 %) with a confidence level of 2/5 but 85% (95% CI 73-93 %) and 100% (95% CI 97-100 %) with a confidence level of 5/5. Greater operator confidence correlates with improved accuracy in FAUS. This should be considered in the development of training guidelines.

Minimum training for right upper quadrant ultrasonography.

The objective of this study was to assess if 10 right upper quadrant (RUQ) ultrasound (US) examinations could be used as a minimum standard for training. This was a retrospective review of patients with suspected gallbladder pathology who underwent resident-performed RUQ US before operative or department of radiology evaluation. Two hundred twenty-four patients were examined using resident-performed RUQ US followed by gold standard evaluations. One hundred seventy-eight patients were evaluated by 13 residents who met the "minimum training" standard of 10 prior examinations. The results of resident-performed RUQ US for gallstones and/or cholecystitis are shown subsequently. Previous suggestions that 10 examinations could be used as a minimum standard for training in focused abdominal sonography for trauma examinations cannot be used for RUQ US. The ACEP 2001 guidelines for 25 examinations are more consistent with the learning curve suggested by our data.

Ultrasonography of the internal jugular vein in patients with dyspnea without jugular venous distention on physical examination.

STUDY OBJECTIVE: Accurate physical examination of patients with dyspnea is important. Jugular venous distention, however, can be difficult to assess in patients. The purpose of this case series is to serve as a pilot study of how ultrasonographic examination of the internal jugular vein compares with other measures of dyspnea. METHODS: This was a case series of 8 patients presenting with dyspnea without jugular venous distention on physical examination. Each patient underwent ultrasonographic examination of the internal jugular vein and inferior vena cava by an emergency physician sonographer blinded to all other clinical information after initial evaluation by another emergency physician for dyspnea. Results of ultrasonographic examination of the internal jugular vein and inferior vena cava were subsequently compared with initial emergency physician physical examination findings, initial chest radiography interpreted by radiologists, initial B-type natriuretic peptide levels, and final hospital discharge diagnosis. RESULTS: Ultrasonographic examination of the internal jugular vein compared more favorably with B-type natriuretic peptide levels and chest radiographic findings than ultrasonographic examination of the inferior vena cava in these patients with dyspnea but not jugular venous distention on physical examination. It was able to identify every patient diagnosed with cardiogenic pulmonary edema on hospital discharge. CONCLUSION: Ultrasonographic examination of the internal jugular vein appears to be helpful in patients who present with dyspnea but do not have evidence of jugular venous distention on physical examination.

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.

Resident-performed compression ultrasonography for the detection of proximal deep vein thrombosis: fast and accurate.

OBJECTIVES: To assess whether emergency medicine residents (EMRs) could quickly perform accurate compression ultrasonography (CUS) for the detection of proximal lower extremity deep vein thromboses (PLEDVTs) with minimal training. METHODS: A prospective, observational study using a convenience sample of patients presenting with signs and/or symptoms for PLEDVT. Vascular laboratory and department of radiology studies were considered the criterion standard. CUS of the femoral vessels was performed. Incompressibility or visualized thrombus was considered "positive." RESULTS: Eight residents with limited ultrasound (US) experience and no prior experience with deep vein thrombosis (DVT) US volunteered to participate in this study, enrolling 72 patients. Their average scan time was 11.7 minutes (95% CI = 9.4 to 14). There were 23 true positives, 4 false positives, 45 true negatives, and 0 false negatives. The test characteristics for PLEDVT gave a sensitivity of 100% (95% CI = 82.2 to 100) and a specificity of 91.8% (95% CI = 79.5 to 97.4). CONCLUSION: Emergency medicine residents with limited US experience were able to quickly perform CUS after minimal training for the detection of PLEDVT in a select group of patients.