WHAT IS IT? Drop in blood pressure of more than 10 mmHg during inspiration phase.
Technically not “paradoxical”. It is merely an exacerbation of normal breathing physiology (small drop in SBP during inspiration)
HOW IS IT DONE? Done via manual blood pressure cuff; inflate above SBP and then deflate slowly (1-2 mmHg per second); the first Korotkoff sound is heard during expiration and then, finally, during both. If the difference between these two pressure readings is the >10 mmHg, it is pulsus paradoxus.
Diff Dx: Used in the evaluation of cardiac tamponade (LR 3.3), pericarditis, COPD, bronchial asthma, restrictive cardiomyopathy, hemorrhagic shock, massive PE, tricuspid stenosis, and mitral stenosis.
Pulsus paradoxus. Olfa Hamzaoui, Xavier Monnet, Jean-Louis Teboul. European Respiratory Journal Dec 2013, 42 (6) 1696-1705; DOI: 10.1183/09031936.00138912
Chapter 8: The Chest: Chest Wall, Pulmonary, and Cardiovascular Systems; The Breasts. DeGowin’s Diagnostic Examination, 10e
Chapter 6: Pulsus Paradoxus. Teaching Rounds: A Visual Aid to Teaching Internal Medicine Pearls on the Wards