What does Kussmaul's sign indicate?

Kussmaul's sign is a clinical sign observed in conditions such as constrictive pericarditis or right heart failure. It refers to the paradoxical rise in central venous pressure (CVP) during inspiration, instead of a decrease that is typically expected during this phase of respiration. The correct answer highlights the phenomenon where the CVP does not increase as expected with inspiration, indicating impaired right heart filling due to conditions that restrict the heart's ability to expand, such as pericardial constriction.

In this context, the inability to raise the CVP with inspiration suggests that the right ventricle is unable to accommodate the increased venous return that normally occurs during inspiration. This response is pivotal for clinicians to recognize, as it can aid in diagnosing specific cardiac conditions that affect hemodynamics. Understanding Kussmaul's sign helps differentiate between typical physiological responses and pathological states in acute care settings.