Pulsus paradoxus

Pulsus paradoxus is the exaggeration of inspiratory fall in pulse volume and in an extreme case the pulse may disappear in inspiration (pulsus paradoxus totalis). The paradox in pulsus paradoxus is that the pulse is not well felt when the heart sounds are audible. Pulsus paradoxus was first described by Kussmaul in 1873, as mentioned by Barr J [1]. Though often considered as a feature of cardiac tamponade, pulsus paradoxus has been described long back in cases of acute laryngitis [2]. It has also been reported rarely in massive pulmonary embolism [3,4]. Correction of pulsus paradoxus noted in cases of shock with infusion of colloids have been documented in 22 of the 30 cases in which it was noted [5].

Pulsus paradoxus is well described in obstructive airways disease, due to wide swings in intrathoracic pressures [6]. Due to the sheer numbers of obstructive airways disease in the community, it will be the commonest cause for pulsus paradoxus. In a series of 76 patients with asthma, pulsus paradoxus was noted in 34. Those with pulsus paradoxus had a more severe airways obstruction.

References

  1. Barr J. The Effects Of Respiration On The Circulation; And The Pulsus Paradoxus Vel Pulsus Inspiratione Intermittens. Br Med J. 1907 Apr 20;1(2416):913-8.
  2. Brockbank EM. Pulsus Paradoxus In Acute Laryngitis. Br Med J. 1893 Jun 24;1(1695):1314-5.
  3. Burdine JA, Wallace JM. Pulsus Paradoxus And Kussmaul’s Sign In Massive Pulmonary Embolism. Am J Cardiol. 1965 Mar;15:413-5.
  4. McDonald IG, Hirsh J, Jelinek VM, Hale GS. Acute major pulmonary embolism as a cause of exaggerated respiratory blood pressure variation and pulsus paradoxus. Br Heart J. 1972 Nov;34(11):1137-41.
  5. Cohn JN, Pinkerson AL, Tristani FE. Mechanism of pulsus paradoxus in clinical shock. J Clin Invest. 1967 Nov;46(11):1744-55.
  6. Rebuck AS, Pengelly LD. Development of pulsus paradoxus in the presence of airways obstruction. N Engl J Med. 1973 Jan 11;288(2):66-9.