Point-of-care Multi-organ Ultrasound Improves Diagnostic Accuracy in Adults Presenting to the Emergency Department With Acute Dyspnea

Daniel Mantuani, MD; Bradley W. Frazee, MD; Jahan Fahimi, MD, MPH; Arun Nagdev, MD

Disclosures

Western J Emerg Med. 2016;17(1):46-53. 

In This Article

Abstract and Introduction

Abstract

Introduction: Determining the etiology of acute dyspnea in emregency department (ED) patients is often difficult. Point-of-care ultrasound (POCUS) holds promise for improving immediate diagnostic accuracy (after history and physical), thus improving use of focused therapies. We evaluate the impact of a three-part POCUS exam, or "triple scan" (TS) – composed of abbreviated echocardiography, lung ultrasound and inferior vena cava (IVC) collapsibility assessment – on the treating physician's immediate diagnostic impression.

Methods: A convenience sample of adults presenting to our urban academic ED with acute dyspnea (Emergency Severity Index 1, 2) were prospectively enrolled when investigator sonographers were available. The method for performing components of the TS has been previously described in detail. Treating physicians rated the most likely diagnosis after history and physical but before other studies (except electrocardiogram) returned. An investigator then performed TS and disclosed the results, after which most likely diagnosis was reassessed. Final diagnosis (criterion standard) was based on medical record review by expert emergency medicine faculty blinded to TS result. We compared accuracy of pre-TS and post-TS impression (primary outcome) with McNemar's test. Test characteristics for treating physician impression were also calculated by dichotomizing acute decompensated heart failure (ADHF), chronic obstructive pulmonary disease (COPD) and pneumonia as present or absent.

Results: 57 patients were enrolled with the leading final diagnoses being ADHF (26%), COPD/asthma (30%), and pneumonia (28%). Overall accuracy of the treating physician's impression increased from 53% before TS to 77% after TS (p=0.003). The post-TS impression was 100% sensitive and 84% specific for ADHF.

Conclusion: In this small study, POCUS evaluation of the heart, lungs and IVC improved the treating physician's immediate overall diagnostic accuracy for ADHF, COPD/asthma and pneumonia and was particularly useful to immediately exclude ADHF as the cause of acute dyspnea.

Introduction

Rapid and accurate diagnosis of the acutely dyspneic patient in the emergency department (ED) is both essential and challenging. Two of the most common causes, acute decompensated heart failure (ADHF) and chronic obstructive pulmonary disease (COPD), differ greatly in both their pathophysiology and treatment, but are often difficult to distinguish clinically in the ED setting.[1–5] Numerous studies indicate that the physical exam, even with the addition of chest radiography, is often inaccurate in differentiating ADHF from COPD/asthma.[1,3–6] Moreover, results of advanced diagnostic imaging (computed tomography, consultative echocardiography) and blood tests (particularly brain naturietic peptide [BNP]) are not available during the critical first minutes. Thus, the emergency physician (EP) is often forced to initiate treatment before the etiology of the patient's respiratory distress can be clearly defined.

Point-of-care ultrasound (POCUS) is emerging as a powerful tool for rapid diagnostic evaluation of ED patients presenting with undifferentiated dyspnea. ADHF, COPD/asthma and other common causes of acute dyspnea all show characteristic findings on POCUS examination of the heart, lungs and inferior vena cava (IVC).[7–11] However, prior studies looking at the examination of each organ individually have generally reported a low specificity in differentiating ADHF from other causes of acute dyspnea.[2,12–14] There are limited data on a combined POCUS examination of the heart, lungs and IVC.[15,16] We have developed and refined a rapid multi-organ exam, dubbed "triple scan" (TS), composed of abbreviated echocardiography, lung ultrasound (US) and IVC exam, which can easily be performed by EPs at the bedside of the acutely dyspneic patient.

If the addition of the TS to the history and physical improves the accuracy of the EP's initial diagnostic impression, its routine use could greatly improve the emergency management of acutely dyspneic patients. The goal of our study was to compare the accuracy of the treating EP's diagnostic impression before and after results of the TS were available, as compared to final diagnosis.

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