Pulsus paradoxus is characterized by which of the following?

• A. An increase in HR during inhalation.
• B. A decrease in BP during inhalation.
• C. An increase in BP during exhalation.
• D. A decrease in HR during exhalation.

Answer: (B)

Pulsus paradoxus is the exaggerated drop in systolic blood pressure during inspiration. Normally, inspiration causes some increase in venous return to the right heart and only a small or no fall in systolic pressure. In conditions like cardiac tamponade, the stiff pericardium limits the heart’s ability to accommodate the extra blood volume that comes with inspiration. The right ventricle bulges, pushing the interventricular septum toward the left ventricle, which reduces left ventricular filling and stroke volume. The result is a noticeable drop in systolic BP when the patient inhales, often more than 10 mm Hg. That inspiratory BP drop is the defining sign of pulsus paradoxus, not changes in heart rate or BP during exhalation.