Vinson D, Zehtabchi S, and Yealy D. (2012). Can selected patients with newly diagnosed pulmonary embolism be safely treated without hospitalization? A systematic review. Ann Emerg Med, 60(5), 651-662. In this systematic review, authors selected published, prospective studies of adult patients with acute, symptomatic, objectively-confirmed pulmonary embolism, who were discharged without admission, to determine if this practice could be done safely. Eight studies—seven observational, one randomized and controlled—were included for a total treatment sample of 777. Inclusion criteria required that original research studies contain symptomatic, acute presentations consistent with pulmonary embolism, clear demographics and comorbidities, radiographic evidence of pulmonary embolism, defined inclusion and exclusion criteria, exclusive outpatient management after initial assessment, an explicit management protocol, and measurable outcomes. Patients receiving home health assistance were not excluded. Initial settings included EDs and outpatient thrombosis units in academic and community centers throughout Canada, Switzerland, Italy, Spain, Netherlands, France, Belgium, and the United States. Some patients in some studies were directly discharged while others were observed for <24 hours. Patients treated in these outpatient settings were first stratified to a low risk category and had no additional clinical criteria warranting admission. No patients were reported lost to follow-up.

 Of all patients in seven of the eight studies (741 patients) reporting ninety-day mortality, none suffered venous thromboembolic-related or hemorrhage-related death. In one study reporting 180-day mortality, there were two thromboembolic-related deaths. In total, there were fifteen non-fatal venous thromboembolic recurrences and four non-fatal major bleeding events. In the one randomized controlled trial, there was an insignificant improvement in patient satisfaction in the outpatient arm versus the impatient arm of the study. 

In sum, this article demonstrates that a large number of appropriately stratified patients have been treated in the outpatient setting with minimal 90-day morbidity or mortality related to thromboembolic disease or hemorrhage. Its major limitations are that it is neither a randomized control trial nor a formal meta-analysis given the heterogeneity of original study designs and populations; therefore, it is limited in scope. In addition, based on the Grading of Recommendations Assessment, Development and Evaluation (GRADE) criteria employed by the authors, seven of the eight studies utilized have an overall “very low” quality of evidence. By its very reliance on this data, the present study therefore also has a “very low” quality of evidence. Nevertheless, this review offers convincing data to propel future research on this topic.

 - Emel 

Bachur RG, Dayan PS, Bajaj L, et al. The Effect of Abdominal Pain Duration on the Accuracy of Diagnostic Imaging for Pediatric Appendicitis. Ann Emerg Med 2012:60(5):582-590. This study was a secondary analysis of a multicenter, prospective observational study to validate and define clinical prediction rule for appendicitis. The primary objective was to determine accuracy of CT and ultrasound imaging for diagnosing pediatric appendicitis as it varied by duration of symptoms. A total of 2,349 patients were enrolled in the parent study, with 1,884 of these patients undergoing imaging with CT (1,016), US (586), or CT + US (282). The study included patients aged 3-18 years old, acute abdominal pain (<72h), imaging with CT or US, and possible appendicitis (blood tests, imaging or surgical consult). Excluded were patients with pregnancy, previous abdominal surgery, chronic GI condition, severe development delay, or imaging prior to ED evaluation. 38% of these patients had appendicitis, with 40.2% undergoing appendectomy (58 had negative operative findings). In the analysis of diagnostic imaging accuracy and duration of symptoms, CT sensitivity (0.98-0.0.96) and specificity (0.97-0.96) did not vary with duration of symptoms, whereas US sensitivity did. US sensitivity varied from 0.79 at <12h of symptoms to 0.96 at 48-71h. Specificity did not vary significantly (0.96-0.98).

The conclusion is that duration of symptoms should be a consideration when ordering and making clinical decisions based on imaging for appendicitis in pediatric patients. CT is sensitive regardless of symptom duration.  Ultrasound is less sensitive for detection of appendicitis when performed on patients with less than 48h of pain.

 - Angell 

Reissig A, Copetti R, Mathis G, et al.  Lung Ultrasound in the Diagnosis and Follow-up of Community-Acquired Pneumonia.  Chest 2012;142(4):965-972. This international prospective, multicenter, observational study looked to evaluate the accuracy of lung ultrasound in the diagnosis of community-acquired pneumonia (CAP) when compared with two-view chest X-ray and, in the case of equivocal or negative radiographic but positive lung ultrasound results, to low-dose CT scan.  Patients with clinically suspected CAP (fever > 38 C, cough, purulent expectoration, dyspnea, and lung breath sounds) were enrolled in the study.  Inclusion criteria were patients with suspected CAP, able to undergo two-view CXR, and age > 18 y/o.  Exclusion criteria were prior abx therapy, HAP, severe immunosuppression, radiographic findings known to the sonographer, and pregnancy.  Lung ultrasound was performed first (or at least 24 hrs from the first CXR).  Scans were performed by experienced physicians who had done at least 100 chest ultrasounds prior.  Three ultrasounds were performed each patient: day 0, days 5-8, and days 13-16. Two CXR were performed, on day 0 and days 13-16.  If there was an inconclusive CXR or positive ultrasound with a negative CXR, then a low-dose CT scan was performed.  They enrolled 362 patients from 14 different European hospitals.  Pneumonia was correctly diagnosed with lung ultrasound in 211 of 226 patients with confirmed CAP, resulting in a sensitivity of 93.4%.  No signs of pneumonia were found in 127 of 130 patients without CAP, resulting in a specificity of 97.7%.  In comparing lung ultrasound to CXR, 26 cases of lung ultrasound CAP were missed by CXR, whereas CXR detected 14 cases of CAP that were missed by ultrasound.  The authors that the sensitivity/specificity of lung ultrasound is comparable to that of two-view chest x-ray.  When comparing radiographic findings with lung ultrasound, CXR missed 7% of the cases detected by ultrasound.  Also, in about 8% of patients, CAP may not be detected by ultrasound because it can only detect lesions reaching the pleura.  As far as limitations go, since two-view chest x-ray was used as the reference test (and it is known to be imperfect), the accuracy of lung ultrasound was likely overestimated.  Also, the patients involved in the study were inpatients.  So it is not known if these results would be able to be translated to an outpatient or emergency department population. 

- Millhouse