A is the correct answer. Why?
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A B-lines on eight-point lung ultrasound
B B-type natriuretic peptide > 100 pg/mL
C Great vessel cephalization on chest X-ray
D Hepatojugular reflux
E Reduced ejection fraction on cardiac ultrasound
Explanation
Acute decompensated heart failure (ADHF) is a heterogeneous clinical syndrome consisting of new or worsening signs of congestive heart failure. While many patients presenting to the ED with ADHF have a history of congestive heart failure, common causes of new ADHF include valvular syndromes, coronary artery disease, myocarditis, and dysrhythmias. The predominant clinical symptom is dyspnea, though patients report a variety of associated symptoms, including peripheral edema, orthopnea, paroxysmal nocturnal dyspnea, and fatigue.
Because dyspnea is a clinical feature of a wide range of conditions, differentiating ADHF from other causes presents a challenge for emergency clinicians. Clinical and diagnostic data vary in their test characteristics and reliability in diagnosing ADHF, with the highest sensitivity associated with B-type natriuretic peptide levels > 100 pg/mL and the highest specificity associated with Kerley B-lines on chest X-ray. However, point-of-care lung ultrasound outperforms nearly all other binary diagnostic tests in both positive and negative likelihood ratios and is the most reliable, independent predictor of ADHF.
An eight-point lung ultrasound exam is performed by scanning two intercostal spaces both anteriorly and laterally on each side. The exam is considered positive if there are at least three B-lines in one intercostal space on each side. A positive exam carries a sensitivity for ADHF of 85%, specificity of 93%, and positive likelihood ratio of 7.4. In facilities with proper equipment and operators with adequate training, point-of-care lung ultrasound provides a more rapid, lower-cost diagnosis of ADHF, with greater accuracy than other diagnostic modalities.
Serum levels of B-type natriuretic peptide > 500 pg/mL are associated with positive likelihood ratios similar to that of positive lung ultrasound, but levels > 100 pg/mL (B) have a positive likelihood ratio of just 2.2.
Great vessel cephalization on chest X-ray (C) and hepatojugular reflux (D) on physical exam are specific for ADHF but do not carry positive likelihood ratios as high as lung ultrasound.
Reduced ejection fraction on cardiac ultrasound (E) has poor sensitivity, specificity, and likelihood ratios when compared to positive lung ultrasound.