Definition

• Pulsus Paradoxus: decreased systolic blood pressure with inspiration
  • Observed in Arterial Line Waveform (see Arterial Line, [[Arterial Line]])

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Etiology

Cardiac

• Cardiogenic Shock (see Cardiogenic Shock, [[Cardiogenic Shock]])
• Constrictive Pericarditis (see Constrictive Pericarditis, [[Constrictive Pericarditis]])
  • Epidemiology: pulsus paradoxus is less common in constrictive pericarditis
• Hypovolemia (see Hypovolemic Shock, [[Hypovolemic Shock]])
  • Epidemiology: in sepsis
  • Respiratory Pulse Pressure Variation, Delta PP ((Max-Min Pulse Pressure)/Average Pulse Pressure), Predicts Cardiac Output Response to an Intravenous Fluid Challenge Better than CVP and PCWP (Am J Resp Crit Care Med, 2000) [MEDLINE]
• Tamponade/Pericardial Effusion (see Tamponade, [[Tamponade]] and Pericardial Effusion, [[Pericardial Effusion]])
  • Epidemiology: pulsus paradoxus is commonly observed in the setting of tamponade
  • Physiology: pulsus paradoxus is observed during spontaneous breathing
  • Diagnosis
    • Echocardiogram
      • Diastolic RV and LV Collapse
      • Systolic RA and LA Collapse
      • Increased Variability in Mitral (>25%) Inflow Velocity
      • Increased Variability in Tricuspid (>40%) Inflow Velocity

Pulmonary

• Acute Pulmonary Embolism (PE) (see Acute Pulmonary Embolism, [[Acute Pulmonary Embolism]])
  • Physiology: RV outflow obstruction
• Asthma (see Asthma, [[Asthma]])
  • Epidemiology: pulsus paradoxus is common in asthma
  • Physiology:
• Chronic Obstructive Pulmonary Disease (COPD) (see Chronic Obstructive Pulmonary Disease, [[Chronic Obstructive Pulmonary Disease]])
  • Physiology:
• Tension Pneumothorax (see Pneumothorax, [[Pneumothorax]])

Other

• Abdominal Compartment Syndrome (see Abdominal Compartment Syndrome, [[Abdominal Compartment Syndrome]])
  • Physiology: due to transmission of high intra-abdominal pressures to thorax -> impaired right-sided venous return
• Anaphylaxis (see Anaphylaxis, [[Anaphylaxis]])
• Superior Vena Cava (SVC) Syndrome (see Superior Vena Cava Syndrome, [[Superior Vena Cava Syndrome]])
  • Physiology: RV inflow obstruction

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References

• Relation between respiratory changes in arterial pulse pressure and fluid responsiveness in septic patients with acute circulatory failure. Am J Respir Crit Care Med. 2000 Jul;162(1):134-8 [MEDLINE]
• Focused critical care echocardiography. Crit Care Med. 2013;41:2618–2626 [MEDLINE]
• Advanced echocardiography for the critical care physician: Part 1. Chest. 2014;145:129–134 [MEDLINE]
• Advanced echocardiography for the critical care physician: Part 2. Chest. 2014;145:135–142 [MEDLINE]