Prospective Validation and Refinement of a Decision Rule to Obtain Chest X-ray in Patients With Nontraumatic Chest Pain in the Emergency Department.

OBJECTIVES: The objective was to prospectively validate and refine previously published criteria to determine the potential utility of chest x-ray (CXR) in the evaluation and management of patients presenting to the emergency department (ED) with nontraumatic chest pain (CP).

METHODS: A prospective observational study was performed of patients presenting to three EDs in the United States with a chief complaint of nontraumatic CP. Previously defined high-risk history and examination elements were combined into a refined decision rule and these elements were recorded for each patient by the ED physician. CXR results were reviewed and analyzed to determine the presence of clinically significant findings including pneumonia, pleural effusion, pneumothorax, congestive heart failure, or the presence of a new mass. Odds ratios for each history and examination element were analyzed as well as sensitivity, specificity, and negative predictive value (NPV) of the rule overall.

RESULTS: A total of 1,111 patients were enrolled and 1,089 CXRs were analyzed. There were 70 (6.4%) patients with clinically relevant findings on CXR. The refined decision rule had a sensitivity of 92.9% (confidence interval [CI] = 83.4%-97.3%) and specificity of 30.4% (CI = 27.6%-33.4%) to predict clinically relevant findings on CXR, with a NPV of 98.4% (CI = 96.1%-99.4%). Five CXRs with clinically significant findings would have been missed by application of the refined rule (three pneumonias and two pleural effusions). Applying these criteria as a CXR decision rule to this population would have reduced CXR utilization by 28.9%.

CONCLUSIONS: This study validates previous research suggesting a low clinical yield for CXR in the setting of nontraumatic CP in the ED. This refined clinical decision rule has a favorable sensitivity and NPV in a patient population with low incidence of disease. Further validation is needed prior to use in practice.