Congestive heart failure (CHF) is a major cause of morbidity and mortality. Early diagnosis of CHF in patients presenting to the emergency department with undifferentiated dyspnea would allow clinicians to begin appropriate treatment more promptly. Current guidelines recommend B-type natriuretic peptide (BNP) levels for more accurate diagnosis of CHF in dyspneic patients. Although BNP levels are relatively inexpensive, the test is not usually performed at bedside and results may take up to an hour or more. BNP also may have a “gray zone” in which the values can neither confirm nor rule out CHF. BNP has a reported sensitivity of 87% and specificity of 74% at a cutoff of 400 pg/ml. Studies investigating bedside ultrasound inferior vena cava (IVC) measurements for identifying CHF report a specificity of 84% to 96% and sensitivity values ranging from 37% to 93%, depending on the study. Given that ultrasound IVC measurements are performed at bedside and results are available rapidly, it is reasonable to evaluate whether ultrasound IVC measurements obtained by appropriately trained emergency department clinicians, alone or in combination with BNP, may increase diagnostic accuracy of CHF
