Pulsus paradoxus is defined as

Pulsus paradoxus is defined as a decrease in systolic blood pressure (BP) of more than 10 mm Hg during normal inspiration. This phenomenon occurs due to the increased negative intrathoracic pressure during inspiration, which exaggerates the normal drop in systolic BP. It is often seen in conditions such as cardiac tamponade, constrictive pericarditis, and severe asthma or COPD exacerbations. References: = CCRN Exam Handbook, AACN Adult CCRN Certification Review Course