Lung ultrasound can be a valuable addition to the emergency physician’s (EP’s) diagnostic armamentarium. This article reviews how this modality may be used to differentiate between chronic obstructive pulmonary disease (COPD) and coronary heart failure (CHF) exacerbations. As patients often have a history of both of these diseases, it is difficult to distinguish which condition is the cause of a patient’s dyspnea. This examination is easy to learn and in most cases, it can be performed within 3 to 4 minutes. Most importantly, lung ultrasound can assist in making clinical decisions in real time at the bedside. Although the following is not a comprehensive review, it does provide the basic essentials, allowing the clinician to begin using this modality in the ED.
Getting Started
The curvilinear probe is required to perform ultrasound of the lungs. Most studies divide the lung into regions, though consensus on exactly how many regions are required remains unclear. The blue protocol, which is probably the most well-known study, divides the lung into the anterior, lateral, and posterolateral sections.1 The superior and inferior aspects of each zone are evaluated with a total of six ultrasound views
per lung.
Artifacts
Lung sliding is movement of the parietal pleura sliding against the visceral pleura. A lines are a repetitive reverberation artifact of the pleura (Figure 1). Occasional comet-tail artifacts—short hyperechoic artifacts that arise from the pleural line and descend in a vertical orientation partially down the screen (Figure 2).
Differential Diagnosis
When using ultrasound to differentiate between CHF and COPD, this examination has been shown to have a sensitivity of 100% and a specificity of 92%.2 By performing lung ultrasound immediately upon a patient’s arrival to the ED, the clinician can obtain quick and accurate insight into whether a patient would benefit from albuterol or nitroglycerin. In the acutely dyspneic patient, combining lung ultrasound with focused echocardiogram and sonographic inferior vena cava assessment will provide additional information to support the diagnosis.
Conclusion
As with other bedside imaging techniques, lung ultrasound in the ED can help to quickly assess the dyspneic patient and facilitate initiation of appropriate treatment.
Dr Taylor is an assistant professor and director of postgraduate medical education, department of emergency medicine, Emory University School of Medicine, Atlanta, Georgia. Dr Meer is an assistant professor and director of emergency ultrasound, department of emergency medicine, Emory University School of Medicine, Atlanta, Georgia. Dr Beck is an assistant professor, department of emergency medicine, Emory University School of Medicine, Atlanta, Georgia.