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Three Part Question

In [patients who present to the emergency department with acute dyspnea], how accurate is [lung ultrasound] in the [diagnosis of acute heart failure]?

Clinical Scenario

A 65 year old male presents to the emergency department with new onset dyspnea. He has no prior history of congestive heart failure. Bedside lung ultrasound is preformed by the emergency physician and found B lines in multiple lung zones. The question is how accurate is bedside lung ultrasound in the diagnosis of acute heart failure?

Search Strategy

Medline 1966-05/17 using PubMed, Cochrane Library 2017, and Embase

(Heart failure/diagnostic imaging OR heart failure/diagnosis) AND (ultrasound OR ultrasonography OR ultrasonics) AND (sensitivity). Limit to English language

Search Outcome

262 studies were identified; one recent meta-analysis addressed the clinical question. This review, published in 2016, considered 8 clinical trials for inclusion. There has been one additional study published which related to the clinical question.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Martindale, JL. et al 6/1/15 United States, Ireland	Adult patient who presented to the Emergency Department with dyspnea as a primary complaint. Lung US performed and interpreted by Emergency Physicians.	Systematic Review	Sensitivity, specificity, and likelihood ratio using presence of at least 3 B lines in two bilateral lung zones for diagnosis of AHF	Lung US 85.3% Sensitivity, 92.7% Specificity, LR+ 7.4, LR- 0.16	No standardized criteria for diagnosis of acute heart failure; non-English studies were excluded; the quality of studies was variable; differences in inclusion and exclusion criteria among the included studies put them at varying degrees of risk for spectrum bias.
Gallard, E. et al 3/2015 France	Patients presenting to the ED for acute dyspnea who had Cardiopulmonary US performed by Emergency Physicians.	Prospective Cohort Study	Sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy	Pulmonary US accuracy of 88% vs 67% for clinical examination and 81% for combination of clinical examination, pro-BNP, and chest xray. Sensitivity 89%, specificity 88%, positive predictive value 92%, negative predictive value 83%, diagnostic accuracy 88%.	Final diagnosis was determined by two independent experts with no defined criteria for AHF. Patients whose hospitalization that was less than 24 hours were excluded which might introduce selection bias to include only patients with more severe disease. Lastly, patients were included in the study only if an ED physician trained in cardiopulmonary ultrasound (3 out of 10 attendings) was available.

Comment(s)

Diagnosing acute heart failure (AHF) in ED patients with undifferentiated dyspnea can be challenging. There are limitations to using clinical history, symptoms, electrocardiography (ECG), natriuretic peptide, and/or chest radiology to determine the diagnosis. In the studies reviewed here, the presence or absence of diffuse B-lines on US provided the most reliable information to confirm or exclude the ED diagnosis of AHF. Compared to a traditional diagnostic evaluation including a chest x-ray, bnp, and clinical exam, lung ultrasound would prevent one additional misdiagnosis in eleven acutely dyspneic emergency department patients.

Clinical Bottom Line

Cardiopulmonary ultrasound has an accuracy of approximately 90% in the evaluation of acute heart failure and has superior test characteristics to traditional diagnostic tests and clinical examination, separately or combined.

References

1. Martindale, JL, Wakai A, Collins SP, Levy PD, Diercks D, Hiestand BC, Fermann GJ, deSouza I, Sinert R Diagnosing Acute Heart Failure in the Emergency Department: A Systematic Review and Meta-analysis Acad Emerg Med 2016 Mar;23(3):223-42
2. Gallard E, Redonnet JP, Bourcier JE, Deshaies D, Largeteau N, Amalric JM, Chedaddi F, Brougeois JM, Garnier D, Geeraerts T Diagnostic Performance of Cardiopulmonary Ultrasound Performed by the Emergency Physician in the Management of Acute Dyspnea AM J Emerg Med 2015 Mar;33(3):352-8