Diagnostic test accuracy of point-of-care ultrasound during cardiopulmonary resuscitation to indicate the etiology of cardiac arrest: A systematic review

Aim: Point-of-care ultrasound (POCUS) is used in cardiac arrest patients to assess for reversible causes. We aimed to conduct a diagnostic test accuracy systematic review of intra-arrest POCUS to indicate the etiology of cardiac arrest in adults in any setting. Methods: This review is registered with PROSPERO (CRD42020205207) and reported according to PRISMA guidelines. We searched Medline, EMBASE, Web of Science, CINAHL, and Cochrane Library on October 6, 2021. Two investigators screened titles and abstracts, extracted data, and assessed risks of bias using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) template. We estimated sensitivity and specificity when feasible and evaluated the certainty of evidence with Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology. Results: Of 8,621 search results, 12 observational studies reported 26 combinations of index tests and reference standards to indicate six different etiologies of cardiac arrest. All studies had high risks of bias from subject selection, lack of blinding, reference standards susceptible to confounding, and/or differential verification. One study reported sufficient data to complete contingency tables for sensitivity and specificity of POCUS to identify myocardial infarction, cardiac tamponade, and pulmonary embolism as the etiology of cardiac arrest. Heterogeneity and risk of bias precluded meta analysis and the certainty of evidence was uniformly very low. Conclusions: It is feasible to identify reversible causes of cardiac arrest with POCUS, but the current literature is heterogenous with high risks of bias, wide confidence intervals, and very low certainty of evidence, which render these data difficult to interpret.