Pulsus paradoxus is defined as...

• A. Blood pressure is higher on expiration than on inspiration by more than 10 mm Hg
• B. Pulse rate increases with inspiration
• C. There is no variation in blood pressure with respiration
• D. Blood pressure is lower on expiration than on inspiration by more than 10 mm Hg

Answer: (A)

Pulsus paradoxus is an exaggerated fall in systolic blood pressure during inspiration. Specifically, systolic pressure drops more than 10 mm Hg with inspiration, so the pressure during expiration is higher than during inspiration by that amount. This occurs because inspiration increases venous return to the right heart and can shift the interventricular septum, reducing left‑ventricular filling and stroke volume, a process that is amplified in conditions like cardiac tamponade and certain obstructive lung diseases. Therefore, saying that blood pressure is higher on expiration than on inspiration by more than 10 mm Hg captures this defining pattern. The other statements describe different or opposite patterns (no variation, or a rise in pressure with inspiration, or the reverse pattern), which do not define pulsus paradoxus.