Pulsus paradoxus

Abstract

Systolic blood pressure normally falls during quiet inspiration in normal individuals. Pulsus paradoxus is defined as a fall of systolic blood pressure of .10 mmHg during the inspiratory phase. Pulsus paradoxus can be observed in cardiac tamponade and in conditions where intrathoracic pressure swings are exaggerated or the right ventricle is distended, such as severe acute asthma or exacerbations of chronic obstructive pulmonary disease. Both the inspiratory decrease in left ventricular stroke volume and the passive transmission to the arterial tree of the inspiratory decrease in intrathoracic pressure contribute to the occurrence of pulsus paradoxus. During cardiac tamponade and acute asthma, biventricular interdependence (series and parallel) plays an important role in the inspiratory decrease in left ventricular stroke volume.Early recognition of pulsus paradoxus in the emergency room can help to diagnose rapidly cardiac tamponade. Measurement of pulsus paradoxus is also useful to assess the severity of acute asthma as well as its response to therapy. Recent development of noninvasive devices capable of automatic calculation and display of arterial pressure variation or derived indices should help improve the assessment of pulsus paradoxus at the bedside.

Pulsus paradoxus

“…Cardiac tamponade, acute asthma, and acute exacerbation of COPD are few prototype clinical scenarios where PP is commonly seen . However; it has been reported in many other clinical conditions.…”

“…However, the impact of spontaneous inspiration on RVSV also depends on the right ventricular volume status. In patients with pre‐existing right ventricular dilation, the right ventricle operates on the flat part of the curve, and the increase in RVSV is smaller (preload‐independency) . Inspiratory augmentation of venous return becomes limited when the RAP falls below atmospheric pressure, with ensuing collapse of the systemic veins entering thorax …”

“…The augmented right heart filling during inspiration increases the intrapericardial pressure, which may cause left heart compression and its underfilling. Augmentation of right ventricular filling during inspiration occurs in both cardiac tamponade and obstructive airway disease, but the fall in ITP in cardiac tamponade is less than that of acute asthma . The increased RVEDV due to augmented venous return decreases left heart filling via bi‐ventricular interaction (both the parallel and series interactions) …”

“…Basically, it is an exaggeration of normal physiologic fall in systolic blood pressure. PP is classically seen in cardiac tamponade, acute asthma, and acute exacerbation of COPD . Patients with cardiac tamponade may develop total paradox or pulse obliteration characterized by inspiratory disappearance of the brachial and radial pulses, with total disappearance of the Korotkoff sounds.…”

Uremic pericarditis, pericardial effusion, and constrictive pericarditis in end‐stage renal disease: Insights and pathophysiology

“…Cardiac tamponade occurs in 20% of patients with dialysis pericarditis . Dialysis‐associated hypotension occurs in 60% of patients in tamponade or pretamponade, as opposed to 6% in those without …”