How is pulsus paradoxus measured in cardiac tamponade?

Updated: Nov 28, 2018
  • Author: Chakri Yarlagadda, MD, FACC, FSCAI, FASNC, CCDS; Chief Editor: Terrence X O'Brien, MD, MS, FACC  more...
  • Print
Answer

To measure the pulsus paradoxus, patients are often placed in a semirecumbent position; respirations should be normal. The blood pressure cuff is inflated to at least 20 mm Hg above the systolic pressure and slowly deflated until the first Korotkoff sounds are heard only during expiration.

At this pressure reading, if the cuff is not further deflated and a pulsus paradoxus is present, the first Korotkoff sound is not audible during inspiration. As the cuff is further deflated, the point at which the first Korotkoff sound is audible during both inspiration and expiration is recorded.

If the difference between the first and second measurement is greater than 12 mm Hg, an abnormal pulsus paradoxus is present.

The paradox is that while listening to the heart sounds during inspiration, the pulse weakens or may not be palpated with certain heartbeats, while S1 is heard with all heartbeats.


Did this answer your question?
Additional feedback? (Optional)
Thank you for your feedback!