Paramedics deliver a 72-year-old male patient with acute shortness of breath to your emergency department (ED). He has already received two rounds of nebulized salbutamol. He is too breathless to provide any history, but a quick review of his medications reveals salbutamol and fluticasone inhalers, enalapril, and acetylsalicylic acid (ASA). He is sitting upright with yellowed fingers from cigarette smoking. He is afebrile with a heart rate of 112 beats per minute, blood pressure of 172/92, respiratory rate of 32, and an oxygen saturation of 94% on a 100% rebreather. He has twoword dyspnea, with wheezes and crackles heard throughout his chest. In addition, you note that he has some mild bilateral leg swelling. Can lung point-of-care ultrasound (POCUS) help?Acute shortness of breath is a common presentation among ED patients and can be challenging to diagnose. Differentiating between acute heart failure and chronic obstructive pulmonary disease (COPD) poses particular difficulty, with similar signs and symptoms found in both. There is no gold standard test for heart failure, and a diagnosis requires the incorporation of a clinical history, physical examination, and initial investigations such as chest radiographs, electrocardiograms, and lab work. Biomarkers such as natriuretic peptides have also been suggested, as have comprehensive echocardiograms, to assess function and anatomy.1,2 As a result, we continue to search for a test that will further help us differentiate between these common clinical entities.In this issue of CJEM, McGivery et al. present the evidence for the use of lung POCUS for the diagnosis of acute heart failure.3 This systematic review and meta-analysis add to the body of literature surrounding the role of lung POCUS, focusing specifically on the ED, and the diagnosis of acute heart failure by the detection of sonographic B-lines. These results strongly support the utility of lung POCUS in the diagnosis of acute heart failure, despite the test characteristics not being as robust as previously reported in other settings. 4,5 Yet, even though lung POCUS still performs much better for the diagnosis of heart failure than chest radiographs, or natriuretic peptides, it still has not been adopted routinely by emergency physicians and is not included in standard clinical guidelines.Why is lung POCUS underused? Perhaps it is because lung POCUS is a novel application of ultrasonography, outside of the traditional comprehensive ultrasound imaging domains of radiology, cardiology, and obstetrics and gynecology.In fact, even in our own discipline of emergency medicine, there continues to be a debate about the acceptance of POCUS as a required competency for all emergency physicians, also highlighted in this issue of CJEM.6 There is mounting evidence that emergency physician performed POCUS is as good as, or nearly as good as, comprehensive imaging for traditional indications such as suspected nephrolithiasis.7 Perhaps there continues to be a debate around POCUS as a core clinical competency because very fe...