There is moderate evidence regarding the effectiveness of interventions to reduce C-spine image ordering in adult patients seen in the ED with neck trauma. Given the national and international focus on improving appropriateness and reducing unnecessary C-spine imaging through campaigns such as Choosing Wisely, additional interventional research in this field is warranted.

While imaging of LBP has been identified as a key area of imaging overuse (e.g., Choosing Wisely recommendation), evidence on interventions to reduce image ordering for ED patients with LBP is sparse. There is some evidence to suggest that interventions can reduce the use of simple imaging in LBP in the ED; however, a shift in imaging modality has also been demonstrated. Additional studies employing higher-quality methods and measuring intervention fidelity are strongly recommended to further explore the potential of ED-based interventions to reduce image ordering for this patient population.

Introduction: Diagnosing pulmonary embolism (PE) can be challenging because the signs and symptoms are often non-specific. Studies have shown that evidence-based diagnostic algorithms are not always adhered to in the Emergency Department (ED), which leads to unnecessary CT scanning. In 2013, the American College of Chest Physicians identified CT pulmonary angiography as one of the top five avoidable tests. One solution is to use a clinical prediction rule combined with the D-dimer, which safely reduces the use of CT scanning. The objective of this study was to compare the proportion of patients tested for PE in two emergency departments, who 1) had a CT-PE and 2) whose diagnosis of PE was missed. We compared these rates to those if the Wells rule and D-dimer had been applied as standard. Methods: This was a retrospective chart review of ED patients investigated for PE at two hospitals from April 2013 to March 2015 (24 months). Inclusion criteria were the ED physician ordered CT-PE, Ventilation-Perfusion (VQ) scan or D-dimer for investigation of PE. Patients under the age of 18 were excluded. PE was defined as CT/VQ diagnosis of acute PE or acute PE/DVT in 30-day follow-up. Trained researchers extracted anonymized data. The rate of CT/VQ imaging and the false-negative rates were calculated. The false-negative rate was calculated as the number of patients diagnosed with PE within 30 days as a proportion of those patients who did not have a CT/VQ scan at initial presentation. Results: There were 1,189 patients included in this study. 55/1,189 patients (4.6%; 95%CI 3.6-6.0%) were ultimately diagnosed with PE within 30 days. 397/1,189 patients (33.4%; 95%CI 30.8-36.1%) had CT/VQ scans for PE. 3 out of 792 who were not scanned had a missed PE resulting in a false-negative rate of 0.4% (95% CI 0.1-1.1%). 80 patients had an elevated D-dimer or high Wells score but were not imaged. Furthermore, 75 patients who did not have an elevated D-dimer nor a high Wells score were imaged. Had Wells rule/D-dimer been adhered to, 402/1,189 patients (33.8%; 95%CI 31.9-36.6%) would have undergone imaging and the false negative rate would be 0/727, 0% (95%CI 0.0-0.5%). Conclusion: If the Wells rule and D-dimer was used in all patients tested for PE, a similar proportion would have a CT scan but fewer PEs would be missed. Keywords: pulmonary embolism, D-dimer, diagnosis LO82The accuracy and prognostic value of point-of-care ultrasound for renal colic: a systematic review C. Wong, MD, P. Young, MD, M. Ross, MD, H. Lee Robertson, MLIS, E. Lang, MD, University of Calgary, Calgary, AB Introduction: Point-of-care ultrasound (POCUS) has been suggested as an initial investigation in the management of renal colic. Our objectives were: 1) to determine the accuracy of POCUS for the diagnosis of nephrolithiasis, and 2) to assess its prognostic value in the management of renal colic (PROSPERO: 42016035331). Methods: An electronic database search of MEDLINE, EMBASE, and PubMed was conducted utilizing subject headings, keywords, and synonyms that addr...

Introduction: Low back pain (LBP) is an extremely frequent emergency department (ED) presentation. Although LBP imaging often results in no change to the ED management, does not identify abnormalities, and has documented risks (e.g., radiation exposure), advanced imaging (i.e., computed tomography [CT], magnetic resonance imaging [MRI]) for patients with LBP has become increasingly frequent in the ED. The objective of this review was to identify and examine the effectiveness and safety of interventions aimed at reducing imaging in the ED for LBP patients. Methods: Six bibliographic databases and grey literature were searched. Comparative studies assessing interventions aimed at reducing ED imaging for adult patients with LBP were eligible for inclusion. Two reviewers independently screened study eligibility, completed data extraction, and assessed the quality of included studies. Due to a limited number of studies and significant heterogeneity, a descriptive analysis was performed. Results: The search yielded 510 unique citations of which three before-after studies were included. Quality assessment identified potential biases relating to comparability between the pre- and post-intervention groups, reliable assessment of outcomes, and an overall lack of information on the intervention (i.e., time point, description, intervention data collection). The interventions to reduce lumbar spine imaging varied considerably. Study interventions included: 1) clinical decision support (i.e., a specialized X-ray requisition form), which reported a 47.4% relative reduction of lumbar spine radiography referrals; 2) clinical decision guidelines, which reduced referrals by 43.8%; and 3) multidisciplinary protocols, which reported a reduction in the MRI referral rate by 26.1%. Despite reductions in simple imaging, CT use increased in two of the three studies. Conclusion: LBP has been identified as a key area of imaging overuse (e.g., Choosing Wisely recommendation). Yet, evidence of interventions’ effectiveness in reducing imaging for ED patients with LBP is sparse. While there is some evidence to suggest that interventions can reduce the use of simple imaging in LBP in the ED, unintended consequences have been reported and additional studies employing higher quality methods are strongly recommended.