What is a positive Kussmaul sign on physical exam?

Kussmaul Sign on Physical Examination

A positive Kussmaul sign is a paradoxical rise in jugular venous pressure (JVP) during inspiration, rather than the normal physiological decrease, indicating impaired right ventricular filling or compliance. 1

Definition and Observation

• Kussmaul sign is best observed by examining the internal jugular vein with the patient positioned at a 45-degree angle 1
• In normal physiology, JVP decreases during inspiration due to increased negative intrathoracic pressure drawing blood into the right atrium 1
• In a positive Kussmaul sign, there is a paradoxical increase in JVP during inspiration, contrary to the normal physiological response 2

Pathophysiology

• The paradoxical rise occurs because the right ventricle cannot accommodate increased venous return during inspiration due to:
  • Impaired right ventricular compliance or filling 1
  • Restricted cardiac chamber expansion during inspiration in conditions like constrictive pericarditis 1
• The rigid pericardium in constrictive pericarditis prevents normal cardiac expansion, leading to increased right atrial pressure during inspiration 1

Clinical Significance and Associated Conditions

• Constrictive pericarditis: Kussmaul sign is a classic finding and important diagnostic criterion 1
• Right ventricular infarction: Often presents with the clinical triad of hypotension, clear lung fields, and elevated JVP including Kussmaul sign 1, 3
• Heart failure: Present in approximately 43% of patients with advanced heart failure and associated with adverse cardiopulmonary hemodynamics 2
• Diabetic ketoacidosis: May be observed along with other signs of dehydration 1, 4
• Other conditions with right heart dysfunction or impaired ventricular filling 1

Diagnostic Value

• Sensitivity of 62.5% and specificity of 90% for right ventricular myocardial infarction in patients with acute inferior myocardial infarction 3
• Positive likelihood ratio of 5.8 for right ventricular myocardial infarction 3
• In heart failure patients, Kussmaul physiology is associated with:
  • Higher pulmonary pressures 2
  • Lower cardiac index 2
  • Reduced pulmonary capacitance 2
  • Greater neurohormonal activation (higher NT-proBNP levels, hyponatremia) 2

Prognostic Implications

• In heart failure patients, the presence of Kussmaul sign is associated with:
  • Higher incidence of post-transplant right ventricular failure 2
  • Higher overall mortality 2
  • Increased risk of adverse cardiac events (hazard ratio 2.18) 5
• Patients with high JVP at rest have even worse prognosis (hazard ratio 3.31) 5

Clinical Pearls

• When evaluating patients with suspected right heart pathology, always assess for Kussmaul sign as it provides valuable diagnostic and prognostic information 1
• The finding should prompt further evaluation with appropriate imaging studies such as echocardiography, CT, or cardiac MRI to determine the underlying cause 1
• In right ventricular myocardial infarction, recognition of Kussmaul sign helps identify patients who require preload-preserving management strategies 3