Emergency department ultrasound for the detection of B-lines in the early diagnosis of acute decompensated heart failure: a systematic review and meta-analysis

Objectives Dyspnea is a common presenting problem that creates a diagnostic challenge for physicians in the emergency department (ED). While the differential diagnosis is broad, acute decompensated heart failure (ADHF) is a frequent cause that can be challenging to differentiate from other etiologies. Recent studies have suggested a potential diagnostic role for emergency lung ultrasound (US). The objective of this systematic review was to assess the accuracy of early bedside lung US in patients presenting to the ED with dyspnea. Methods A systematic search of EMBASE, PubMed, and the Cochrane Library was performed in addition to a grey literature search. We selected prospective studies that reported on the sensitivity and specificity of B-lines from early lung ultrasound in dyspneic patients presenting to the ED. Selected studies underwent quality assessment using the Critical Appraisal and Skills Program (CASP) questionnaire. Data Extraction and Synthesis The search yielded 3674 articles; seven studies met inclusion criteria and fulfilled CASP requirements for a total of 1861 patients. Summary statistics from the meta-analysis showed that as a diagnostic test for ADHF, bedside lung US had a pooled sensitivity of 82.5% (95% confidence interval [CI]=66.4% to 91.8%) and a pooled specificity of 83.6% (95% CI=72.4% to 90.8%). Conclusions Our results suggest that in patients presenting to the ED with undifferentiated dyspnea, B-lines from early bedside lung US may be reliably used as an adjunct to current diagnostic methods. The incorporation of lung US may lead to more appropriate and timely diagnosis of patients with undifferentiated ADHF.