Article Summary
1. Why is this topic important? Pneumonia, acute heart failure, and exacerbation of chronic obstructive pulmonary disease
Acute respiratory symptoms are frequent causes of emergency department (ED) visits, and respiratory impairment is a leading cause of hospital ward and intensive care unit (ICU) admissions. The differential diagnosis includes common pulmonary and cardiovascular diseases such as pneumonia, exacerbations of chronic pulmonary diseases, and acute heart failure syndromes, which may lead to rapid clinical deterioration. Thus, an immediate and accurate diagnosis is critical, because failure of, or delay in, diagnoses and treatment can have detrimental effects on patients. Delay in administering adequate antimicrobial therapy can increase the mortality in patients with pneumonia, and inadequate administration of beta-agonists can impair the cardiovascular function in patients with acute heart failure 1, 2.
Chest radiography (CXR) is currently the first diagnostic imaging approach in patients with acute respiratory symptoms. However, several studies report CXR having poor sensitivity for detecting common respiratory diseases such as pneumonia and pulmonary edema from acute heart failure 3, 4. Chest computed tomography (CCT) overcomes this limitation but increases costs and exposure to radiation, and patients need to be transported to the radiology department (5).
In the past decade, lung ultrasound (LUS) has attracted attention in emergency and intensive care medicine. It is radiation free, can be performed at the bedside in a few minutes, and can be interpreted in real time for multiple diagnoses. Along with other point-of-care ultrasound modalities, LUS accelerates the diagnostic process, increases the rate of correct diagnoses, and ensures appropriate treatment in the first hours after arrival at the ED 6, 7. However, diagnostic accuracy studies have assessed different sonographic signs and subgroups of patients, with different values of sensitivity and specificity, even for the same target disease 8, 9, 10.
The aim of this systematic review and meta-analysis was to assess the accuracy of LUS for the emergency diagnosis of the most common diseases in adults with respiratory symptoms. We systematically reviewed the literature for prospective diagnostic accuracy studies of LUS for pneumonia, acute heart failure, and exacerbations of chronic obstructive pulmonary disease (COPD)/asthma. In addition to the overall diagnostic accuracy of LUS for these diseases, we measured the individual diagnostic accuracy of the different sonographic signs that were presented in the literature.
The protocol of this review was prospectively registered in the International Prospective Register of Systematic Reviews (PROSPERO; Centre for Reviews and Dissemination, University of York, York, UK; CRD42016048085). The review is reported according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines (11).
Two independent authors (LJS and RRMB) selected the studies, extracted their data, and assessed their risk of bias and applicability concerns.
From the 11,017 titles and abstracts screened, 25 studies involving 4241 patients were included. Fourteen studies assessed pneumonia (n = 1867 patients), 14 assessed acute heart failure (n = 2778 patients), and four studies assessed exacerbation of COPD or asthma (n = 527 patients) 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40. Figure 1 shows the study selection process.
All included studies were published between 2008 and 2016. Most of them
This study systematically reviewed the available literature for prospective studies on the accuracy of the LUS for the emergency diagnosis of pneumonia, acute heart failure, and exacerbations of COPD/asthma. Twenty-five studies were included, most of which had assessed pneumonia and acute heart failure. The studies were heterogeneous in their characteristics and results, and the overall methodological quality was low, demanding cautious interpretation of the findings. The meta-analysis suggests
LUS has high accuracy for pneumonia, acute heart failure, and exacerbation of COPD/asthma, and seems to be a valuable complement to other diagnostic methods in the emergency diagnosis of these diseases in adults with respiratory symptoms. The interpretation of the LUS examination should take into account the accuracy of the individual sonographic signs to diagnose pneumonia and acute heart failure. 1. Why is this topic important? Pneumonia, acute heart failure, and exacerbation of chronic obstructive pulmonary diseaseArticle Summary
The authors appreciate the assistance of Maria Gorete Monteguti Savi for her help with the database search strategy.
However, the situation would be improved if pulmonary ultrasound was employed. Several studies supported that pulmonary ultrasound could be used to distinguish COPD from cardiogenic pulmonary edema and dyspnea due to other diseases.3,4 In addition, the data supported that B-lines in COPD exacerbations could be detected by pulmonary ultrasound.5