Today in
Cardiology clinic, I was preparing to see a patient who had a history of
pericardial thickening, among other cardiac issues. Before going in for my assessment, my preceptor
reminded me to screen for any symptoms of constrictive pericarditis and to
examine for the presence of pulsus paradoxus. I took a moment to review the
significance of pulsus paradoxus and how to perform this measurement.
Pulsus
paradoxus refers to an exaggerated fall in a patient's blood pressure during
inspiration by greater than 10 mmHg. It is caused by changes in the mechanical
forces imposed on the chambers of the heart and pulmonary vasculature. The
exact pathophysiology is quite complex and varies depending on the etiology,
with several mechanisms involved. Pulsus paradoxus is often associated with
pericardial disease, often cardiac tamponade and to a lesser extent
constrictive pericarditis. However this finding can also been seen in
non-pericardial diseases (such as right ventricular MI, restrictive
cardiomyopathy), as well as non-cardiac diseases (severe COPD, asthma, tension
pneumothorax).
Pulsus
paradoxus is measured using a manual sphygmomanometer and stethoscope.
Assessment is made by inflating the cuff until the Korotkoff sounds are absent.
The cuff is than deflated very slowly. The first sounds auscultated will be
heard only during expiration, and this pressure should be noted. As the cuff
pressure is dropped further, the pressure when Korotkoff sounds are heard
during both inspiration and expiration should be noted. The variation between
these 2 systolic pressures is what quantifies pulsus paradoxus. Pulsus
paradoxus can also be quantified by an invasive arterial measurement.
An important tip when
assessing for pulsus paradoxus is to ensure the patient is breathing normally. Do
not instruct them to change their breathing pattern as the depth of respiration
influences the magnitude of pulsus paradoxus!
In the end, there was no finding of pulsus paradoxus in our patient and she had no clinical symptoms
of pericardial disease. This was a great opportunity to review the significance
of this physical exam finding and practice performing it in a real-life setting!
-MB-
References:
- Van Dam MN, Fitzgerald BM. Pulsus Paradoxus. [Updated 2019 Jun 4]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing.
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