What causes pulsus paradoxus in status asthmaticus?

Updated: Jun 17, 2020
  • Author: Constantine K Saadeh, MD; Chief Editor: John J Oppenheimer, MD  more...
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Answer

Pulsus paradoxus (a decrease in the systolic blood pressure during inspiration) results from a decrease in cardiac stroke volume with inspiration due to greatly increased left-ventricular afterload. This increase is generated by the dramatic increase in negative intrapleural and transmural pressure in a patient struggling to breathe against significant airways obstruction. Pulsus paradoxus of greater than 20 mm Hg correlates well with the presence of severe airways obstruction (ie, forced expiratory volume in 1 second [FEV1] < 60% predicted).


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