A 64 year old woman presents to the emergency department with dyspnea. On exam she is mildly tachypneic, has an oxygen saturation of 94% on 2L nasal prongs, and bilateral crackles to auscultation. You suspect acute heart failure and wonder about the role of lung ultrasound as you await her chest x-ray. Clinical question: What is the sensitivity and specificity of lung PoCUS compared to chest radiograph for diagnosis of acute decompensated …