Ralph Wang

Radiological Imaging of Patients with Suspected Urinary Tract Stones: National Trends, Diagnoses, and Predictors

OBJECTIVES Overutilization of computed tomography (CT) is a growing public health concern due to increasing health care costs and exposure to radiation; these must be weighed against the potential benefits of CT for improving diagnoses and treatment plans. The objective of this study was to determine the national trends of CT and ultrasound (US) utilization for assessment of suspected urolithiasis in emergency departments (EDs) and if these trends are accompanied by changes in diagnosis rates for urolithiasis or other significant disorders and hospitalization rates. METHODS This was a retrospective cross-sectional analysis of ED visits from the National Hospital Ambulatory Medical Care Survey (NHAMCS) between 1996 and 2007. The authors determined the proportion of patient visits for flank or kidney pain receiving CT or US testing and calculated the diagnosis and hospitalization rates for urolithiasis and other significant disorders. Patient-specific and hospital-level variables associated with the use of CT were examined. RESULTS Utilization of CT to assess patients with suspected urolithiasis increased from 4.0% to 42.5% over the study period (p < 0.001). In contrast, the use of US remained low, at about 5%, until it decreased beginning in 2005 to 2007 to 2.4% (p = 0.01). The proportion of patients diagnosed with urolithiasis (approximately 18%, p = 0.55), with other significant diagnoses (p > 0.05), and admitted to the hospital (approximately 11%, p = 0.49) did not change significantly. The following characteristics were associated with a higher likelihood of receiving a CT scan: male sex (odd ratio [OR] = 1.83, 95% confidence interval [CI] = 1.22 to 2.77), patients presenting with severe pain (OR = 2.96, 95% CI = 1.14 to 7.65), and those triaged in 15 minutes or less (OR = 2.41, 95% CI = 1.08 to 5.37). CT utilization was lower for patients presenting to rural hospitals (vs. urban areas; OR = 0.34, 95% CI = 0.19 to 0.61) and those managed by a nonphysician health care provider (OR = 0.19, 95% CI = 0.07 to 0.53). CONCLUSIONS From 1996 to 2007, there was a 10-fold increase in the utilization of CT scan for patients with suspected kidney stone without an associated change in the proportion of diagnosis of kidney stone, diagnosis of significant alternate diagnoses, or admission to the hospital.

Ultrasound-guided supraclavicular brachial plexus nerve block vs procedural sedation for the treatment of upper extremity emergencies

BACKGROUND Emergency physicians often treat patients who require procedural sedation for the management of upper extremity fractures, dislocations, and abscesses (upper extremity emergencies). Unfortunately, procedural sedation is associated with several rare but potentially serious adverse effects and requires continuous hemodynamic monitoring and several dedicated staff members. The purpose of this study was to determine the role of ultrasound-guided supraclavicular brachial plexus nerve blocks in the emergency department (ED) as an alternative to procedural sedation for the management of upper extremity emergencies. METHODS In a prospective trial, a convenience sample of ED patients with upper extremity emergencies that would normally require procedural sedation were assigned to receive either procedural sedation or an ultrasound-guided supraclavicular brachial plexus nerve block. Emergency department length of stay (ED LOS) was the primary outcome measure and was analyzed using a paired 2-tailed Student t test. RESULTS A total of 12 subjects were enrolled. Average ED LOS for subjects receiving the brachial plexus nerve block was 106 minutes (95% confidence interval, 57-155 minutes). Average ED LOS for subjects receiving procedural sedation was 285 minutes (95% confidence interval, 228-343 minutes). The ED LOS was significantly shorter in the nerve block group (P < .0005). Patient satisfaction was high in both groups, and no significant complications occurred in either group. CONCLUSIONS In our population, ultrasound-guided brachial plexus nerve blocks resulted in shorter ED LOS compared to procedural sedation for patients with upper extremity fractures, dislocations, or abscesses.

Emergency physician ultrasonography for evaluating patients at risk for ectopic pregnancy: a meta-analysis

STUDY OBJECTIVE Ectopic pregnancy is a common concern in emergency departments (EDs) and remains the leading cause of first-trimester mortality. Pelvic ultrasonography by emergency physicians has been investigated as a diagnostic test for ectopic pregnancy. We present a meta-analysis of the use of emergency physician ultrasonography in the evaluation of patients at risk of ectopic pregnancy. METHODS A structured search was performed of both MEDLINE and EMBASE. Inclusion criteria were that (1) the study reported original research on ED patients at risk for ectopic pregnancy; (2) an emergency physician performed and interpreted the initial pelvic ultrasonography; and (3) follow-up was conducted on all patients. Sensitivity was defined as the proportion of patients with ectopic pregnancy for which ED ultrasonography demonstrated no intrauterine pregnancy. A random-effects model was used to obtain summary test characteristics. RESULTS The initial search showed 576 publications, abstract review yielded 60 with potential relevance, and 10 studies were included. There was a total of 2,057 patients, of whom 152 (7.5%) had ectopic pregnancy. The pooled sensitivity estimate was 99.3% (95% confidence interval [CI] 96.6% to 100%), negative predictive value was 99.96% (95% CI 99.6% to 100%), and negative likelihood ratio was 0.08 (95% CI 0.025 to 0.25), all without significant heterogeneity. CONCLUSION The results of this meta-analysis suggest that in a wide variety of clinical settings, the use of bedside ultrasonography performed by emergency physicians as a diagnostic test for ectopic pregnancy provides excellent sensitivity and negative predictive value. Visualization of an intrauterine pregnancy by an emergency physician is generally sufficient to rule out ectopic pregnancy.

External Validation of the STONE Score, a Clinical Prediction Rule for Ureteral Stone: An Observational Multi-institutional Study

Study objective The STONE score is a clinical decision rule that classifies patients with suspected nephrolithiasis into low-, moderate-, and high-score groups, with corresponding probabilities of ureteral stone. We evaluate the STONE score in a multi-institutional cohort compared with physician gestalt and hypothesize that it has a sufficiently high specificity to allow clinicians to defer computed tomography (CT) scan in patients with suspected nephrolithiasis. Methods We assessed the STONE score with data from a randomized trial for participants with suspected nephrolithiasis who enrolled at 9 emergency departments between October 2011 and February 2013. In accordance with STONE predictors, we categorized participants into low-, moderate-, or high-score groups. We determined the performance of the STONE score and physician gestalt for ureteral stone. Results Eight hundred forty-five participants were included for analysis; 331 (39%) had a ureteral stone. The global performance of the STONE score was superior to physician gestalt (area under the receiver operating characteristic curve=0.78 [95% confidence interval {CI} 0.74 to 0.81] versus 0.68 [95% CI 0.64 to 0.71]). The prevalence of ureteral stone on CT scan ranged from 14% (95% CI 9% to 19%) to 73% (95% CI 67% to 78%) in the low-, moderate-, and high-score groups. The sensitivity and specificity of a high score were 53% (95% CI 48% to 59%) and 87% (95% CI 84% to 90%), respectively. Conclusion The STONE score can successfully aggregate patients into low-, medium-, and high-risk groups and predicts ureteral stone with a higher specificity than physician gestalt. However, in its present form, the STONE score lacks sufficient accuracy to allow clinicians to defer CT scan for suspected ureteral stone.

Effect of Tamsulosin on Stone Passage for Ureteral Stones: A Systematic Review and Meta-analysis

Study objective: Tamsulosin is recommended for patients receiving a diagnosis of a ureteral stone less than 10 mm who do not require immediate urologic intervention. Because of conflicting results from recent meta‐analyses and large randomized controlled trials, the efficacy of tamsulosin is unclear. We perform a systematic review and meta‐analysis to investigate the effect of tamsulosin on stone passage in patients receiving a diagnosis of ureteral stone. Methods: MEDLINE, EMBASE, and CENTRAL databases were searched without language restriction through November 2015 for studies assessing the efficacy of tamsulosin and using a double‐blind, randomized, controlled trial design. Meta‐analysis was conducted with a random‐effects model and subgroup analyses were conducted to determine sources of heterogeneity. Results: Eight randomized controlled trials (N=1,384) contained sufficient information for inclusion. The pooled risk of stone passage in the tamsulosin arm was 85% versus 66% in the placebo arm, but substantial heterogeneity existed across trials (I2=80.2%; P<.001). After stratifying of studies by stone size, the meta‐analysis of the large stone subgroup (5 to 10 mm; N=514) indicated a benefit of tamsulosin (risk difference=22%; 95% confidence interval 12% to 33%; number needed to treat=5). The meta‐analysis of the small stone subgroup (<4 to 5 mm; N=533) indicated no benefit (risk difference=–0.3%; 95% confidence interval –4% to 3%). Neither meta‐analysis for the occurrence of dizziness or hypotension showed a significant effect. Conclusion: Tamsulosin significantly improves stone passage in patients with larger stones, whereas the effect of tamsulosin is diminished in those with smaller stones, who are likely to pass their stone regardless of treatment.

Emergency Department Imaging Modality Effect on Surgical Management of Nephrolithiasis: A Multicenter, Randomized Clinical Trial.

Purpose: In the emergency department ultrasonography is emerging as an alternative to computerized tomography for diagnosing patients with nephrolithiasis. In this multicenter randomized clinical trial we examined rates of urological referral and intervention to elucidate whether the initial diagnostic imaging modality affected the management of nephrolithiasis. Materials and Methods: Patients 18 to 76 years old who presented to the emergency department with renal colic across 15 diverse treatment centers were randomized to receive abdominal ultrasonography by an emergency department physician or a radiologist, or abdominal computerized tomography. We analyzed the 90‐day followup for patients diagnosed with nephrolithiasis to assess subsequent urological evaluation, procedure type and time to intervention. Results: Of 1,666 patients diagnosed with nephrolithiasis in the emergency department 241 (14.5%) had a consultation with urology at initial presentation, 503 (30%) saw a urologist in followup and 192 (12%) underwent at least 1 urological procedure. Median time to outpatient procedure and type of procedure performed did not vary significantly among imaging groups. Most patients (78%) had computerized tomography performed before elective intervention. Patients with ultrasonography performed by an emergency department physician were 2.6 times more likely to undergo computerized tomography before intervention than those who had ultrasonography performed by a radiologist. Conclusions: Patients undergoing a urological intervention who had ultrasonography as initial imaging do not experience a significant delay to intervention or different procedure types, but the majority ultimately undergoes computerized tomography before surgery. Formal ultrasonography by a radiologist may encourage less computerized tomography preoperatively.

The Absence of Gallstones on Point-of-Care Ultrasound Rules Out Acute Cholecystitis.

BACKGROUND Cholelithiasis affects an estimated 20 million people in the United States yearly; 20% of symptomatic patients will develop acute cholecystitis (AC). A recent single-center study estimating test characteristics of point-of-care ultrasonography (POCUS) for the detection of AC, as defined by gallstones plus sonographic Murphys or pericholecystic fluid or gallbladder wall-thickening, resulted in a sensitivity and specificity of 87% (95% confidence interval [CI] 66-97) and 82% (95% CI 74-88), respectively. No prior studies have been conducted to estimate the test characteristics of POCUS for the purpose of excluding acute calculous cholecystitis. OBJECTIVE To determine whether the finding of gallstones alone on POCUS has high sensitivity, high negative predictive value, and low negative likelihood ratio for the exclusion of AC. METHODS We conducted an analysis using data from a prospective cross-sectional single-center study of POCUS test to estimate the test characteristics using a simplified definition of a positive test - the presence of gallstones alone. Clinical follow-up and pathology reports were used as the reference standard. Test characteristics were calculated and compared to the standard definition, gallstones plus one secondary finding. RESULTS The overall prevalence of AC was 14% (23 pathology-confirmed cases of 164 included patients). The sensitivity of the simplified definition was 100% (95% CI 85.7-100), negative predictive value 100% (95% CI 92.2-100), and negative likelihood ratio was < 0.1, compared to a sensitivity of 87% (95% CI 66-97%), negative predictive value 97% (95% CI 93-99%), and negative likelihood ratio of 0.16 (95% CI 0.06-0.5). CONCLUSION Simplifying the definition of the test findings on POCUS to gallstones alone has excellent sensitivity and negative predictive value for the exclusion of AC. This finding, if broadly validated prospectively, confirms the practice of excluding acute calculous cholecystitis using POCUS in emergency department patients.

Medical expulsive therapy use in emergency department patients diagnosed with ureteral stones

Objective Recent studies have clarified the role of alpha‐blockers, such as tamsulosin, for patients diagnosed with ureteral stones < 10 mm not requiring an urgent intervention. Prior studies have reported low rates of use of MET by emergency physicians. We sought to describe patterns of alpha‐blocker use and to determine factors associated with utilization in patients diagnosed with ureterolithiasis in the ED. Methods We used data from a randomized trial of CT scan vs. ultrasound in participants with suspected urolithiasis enrolled at 15 EDs between October 2011 and February 2013. The use of medical expulsive therapy was identified by the prescription of an alpha‐blocker, calcium channel blocker, or steroid at the ED visit. The prevalence of alpha‐blocker use in participants with ureteral stones on imaging was calculated, and multivariable models were used to examine risk factors for utilization. Results Of the 524 participants who were identified with a ureteral stone on CT scan and discharged from the ED, 375 (71.4%) received an alpha‐blocker, and 2 (< 1%) received a steroid. There was no significant difference in alpha‐blocker use for participants based on stone size or location. However, there was a 3.6‐fold difference in alpha‐blocker use between the lowest and highest use ED sites. In the multivariable analysis, ED site was independently associated with utilization of alpha‐blockers. Conclusions Alpha‐blockers were prescribed in more than two‐thirds of patients with a distal ureteral stone on imaging, a much higher prevalence than previously reported. There was substantial variability in alpha‐blocker use based on ED site.

Detection of Acute Pulmonary Embolism by Bedside Ultrasound in a Patient Presenting in PEA Arrest: A Case Report

Optimal management of the critically ill patient in shock requires rapid identification of its etiology. We describe a successful application of an emergency physician performed bedside ultrasound in a patient presenting with shock and subsequent cardiac arrest. Pulmonary embolus was diagnosed using bedside echocardiogram and confirmed with CTA of the thorax. Further validation and real-time implementation of this low-cost modality could facilitate the decision to implement thrombolytics for unstable patients with massive pulmonary embolism who cannot undergo formal radiographic evaluation.

Visual Stimulus: Splinter Localization with Ultrasound

*Department of Emergency Medicine, University of California, San Francisco, San Francisco, California, †Department of Emergency Medicine, Alameda County Medical Center – Highland Campus, Oakland, California, and ‡Department of Medicine, University of California, San Francisco, San Francisco, California Reprint Address: Ralph Wang, MD, Department of Emergency Medicine, University of California, San Francisco, 505 Parnassus Ave., San Francisco, CA 94117