BLUE protocol ultrasonography in Emergency Department patients presenting with acute dyspnea

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Abstract

Objective

Dyspnea is a common Emergency Department (ED) symptom requiring prompt diagnosis and treatment. The bedside lung ultrasonography in emergency (BLUE) protocol is defined as a bedside diagnostic tool in intensive care units. The aim of this study was to investigate the test performance characteristics of the BLUE-protocol ultrasonography in ED patients presenting with acute dyspnea.

Method

This study was performed as a prospective observational study at the ED of a tertiary care university hospital over a 3-month period. The BLUE-protocol was applied to all consecutive dyspneic patients admitted to the ED by 5 emergency physicians who were certified for advanced ultrasonography. In addition to the BLUE-protocol, the patients were also evaluated for pleural and pericardial effusion.

Results

A total of 383 patients were included in this study (mean age, 65.5 ± 15.5 years, 183 (47.8%) female and 200 (52.2%) male). According to the BLUE-protocol algorithm, the sensitivities and specificities of the BLUE-protocol are, respectively, 87.6% and 96.2% for pulmonary edema, 85.7% and 99.0% for pneumonia, 98.2% and 67.3% for asthma/COPD, 46.2% and 100% for pulmonary embolism, and 71.4% and 100% for pneumothorax. Although not included in the BLUE-protocol algorithm, pleural or pericardial effusion was detected in 82 (21.4%) of the patients.

Conclusion

The BLUE-protocol can be used confidently in acute dyspneic ED patients. For better diagnostic utility of the BLUE-protocol in EDs, it is recommended that the BLUE-protocol be modified for the assessment of pleural and pericardial effusion. Further diagnostic evaluations are needed in asthma/COPD groups in terms of the BLUE-protocol.

Introduction

Dyspnea is a common and life-threatening symptom among patients admitted to Emergency Departments (EDs). Therefore, the rapid and accurate diagnosis of the pathology causing dyspnea is essential [1,2]. The many potential causes of dyspnea makes it difficult to form a simple algorithm for dyspnea diagnosis [3]. Although traditional methods, such as physical examination and chest X-rays, are the most frequently used methods in the differential diagnosis of dyspnea, they remain insufficient for final diagnosis. Chest computerized tomography (CT) is currently the most sensitive and feasible modality for diagnosing most lung pathologies, such as pneumonia, pneumothorax, pulmonary thromboembolism, and interstitial lung diseases; however, CT has significant limitations, such as exposure to ionized radiation, limited application in certain patients, such as pregnant women, the necessity of transferring a potentially unstable patient to the tomography unit, and difficulty in accessing CT equipment [2].

Lung ultrasonography (LUS)1 has been used successfully as a bedside diagnostic tool for diagnosing thoracic and cardiovascular pathologies, especially for acute decompensated heart failure, pneumonia, pneumothorax, pulmonary thromboembolism (PTE), pleural-pericardial effusion, and empyema [4]. This method has been shown to produce superior results compared with other methods, such as physical examination, chest X-rays, and CT, in studies conducted using LUS [5]. LUS is also advantageous because it can be performed at bedside, carries no risk of ionizing radiation, and can easily be implemented by emergency physicians, who can interpret findings together with other clinical signs and symptoms [6].

The bedside lung ultrasonography in emergency (BLUE)2 protocol is an algorithm developed by Lichtenstein as a systemic approach to the diagnosis of patients with dyspnea in intensive care units (ICUs) with 90.5% diagnostic accuracy. Although the BLUE protocol is highly effective in diagnosing dyspneic patients, it was developed for use in intensive care patients [6]. Few studies have examined the utility of LUS with the BLUE protocol in the diagnosis of patients presenting with acute dyspnea in EDs. The aim of this study was to investigate the test performance characteristics of the BLUE protocol in detecting the causes of dyspnea in ED patients presenting with acute dyspnea.

Section snippets

Study design

This prospective cross-sectional study was conducted at a tertiary care university hospital with an annual census of about 55.000 ED visits covering a period of 3 months between December 01, 2012 and February 28, 2013.

All consecutive patients aged >18 years admitted to the ED with a primary complaint of acute dyspnea and who consented to participate were included in this study. Patients younger than 18, patients who refused to participate and were not given a definitive diagnosis during

Results

All 458 patients admitted to the ED with primary complaints of dyspnea for 3 months were initially included in the study. Of them, 75 patients met the exclusion criteria and were therefore excluded from the study. A total of 383 patients (200 male and 183 female, mean age 65.0) were ultimately included in the study. Detailed information related to the characteristics of the dyspneic ED patients included in the study is given in Table 1.

Standard tests and diagnostic imaging modalities were

Discussion

The BLUE protocol is a method developed to diagnose patients with dyspnea in ICUs. In this study, we evaluated the utility of the BLUE protocol in the ED. The rate of correct diagnosis of the BLUE protocol algorithms in all diseases was 77.5%. The overall accuracy of the original BLUE protocol study presented by Lichtenstein was 90.5% [6].

The overall diagnostic accuracy of our study was lower than that of the Lichtenstein study. This was due to the fact that dyspneic patients who presented to

Conclusion

The BLUE protocol algorithm designed for intensive care patients can also be used confidently in the evaluation of acute dyspneic ED patients, especially in the diagnosis of heart failure, pneumothorax, pneumonia, and pulmonary embolism. However, as the most important result of our study, we believe that the BLUE protocol can fail in the diagnosis of asthma/COPD with low sensitivity and specificity values when evaluating ED patients with acute dyspnea. Further diagnostic evaluations are needed

Acknowledgements

None.

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.

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