STEP2: CARDS: Pulses

Question 1

In what conditions might you observe this BP finding?

Answer 1

Constrictive pericarditis
Cardiac tamponade
Severe obstructive airway disease (asthma, COPD)
Obstructive sleep apnea
Croup
Tension pneumothorax
Superior vena cava syndrome

What is this finding:
Pulsus paradoxus: pathological decrease in the pulse wave amplitude and systolic blood pressure > 10 mm Hg during inspiration

Decrease of intrathoracic pressure during inspiration → expansion of vena cava and right atrium → ↑ venous return → ↑ RV filling

↓ Pericardial compliance (e.g., due pericardial rigidity in constrictive pericarditis) → ↑ bowing of the ventricular septum into the left ventricle → ↓ LV ejection volume → ↓ systolic blood pressure