Pulsus paradoxus Paradoxical pulse

• Facts:
  Exaggeration of the normal variation during inspiratory phase of respiration
  
  Caused by decreased blood flow to left heart from lung hyperinflation (increased preload to R heart during inspiration)
• Diagnosis:
  Difference in systolic blood pressure of > 12 mmHg during inspiration
• Associated With:
  1) Cardiac tamponade
  2) Tension pneumothorax
  3) Obstructive lung disease (eg. severe asthma , COPD )