Pulsus paradoxus (paradoxical pulse) is an exaggerated decline in systolic blood pressure during inspiration. Normally, systolic pressure decreases by less than 10 mm Hg during inspiration. In pulsus paradoxus, the decrease exceeds 10 mm Hg, and when it exceeds 20 mm Hg, peripheral pulses may be barely palpable or even disappear during inspiration.

This phenomenon results from an exaggerated inspiratory increase in negative intrathoracic pressure, which reduces left ventricular filling, stroke volume, and transmits negative pressure to the aorta. Conditions that cause large intrapleural pressure swings, such as asthma, or that impair left-sided heart filling, such as pericardial tamponade, commonly produce pulsus paradoxus.

Detection

• Sphygmomanometer method: Inflate cuff 10–20 mm Hg above systolic pressure. Slowly deflate (≈2 mm Hg/sec). Note the first Korotkoff sound during expiration. Continue deflation, observing disappearance of sounds during inspiration. Subtract the pressures to determine the degree of paradox (>10 mm Hg is abnormal).

• Palpation method: Assess radial pulse over several respiratory cycles. Marked pulse diminution during inspiration indicates pulsus paradoxus.

• Rule out irregular heart rhythms or tachycardia, which can mimic this sign.

Emergency interventions

• Rapidly assess vital signs.

• Evaluate for cardiac tamponade: dyspnea, tachypnea, diaphoresis, jugular vein distention, tachycardia, narrowed pulse pressure, hypotension.

• Prepare for emergency pericardiocentesis if tamponade is suspected.

• Monitor degree of paradox to assess response after intervention.

History and Physical Examination

• Assess for chronic cardiac or pulmonary disease.

• Ask about cough, chest pain, dyspnea, and associated symptoms.

• Auscultate for abnormal breath or heart sounds.

Medical causes

Special considerations

• Prepare for echocardiography to visualize cardiac motion and determine the underlying disorder.

• Monitor vital signs and frequency of paradox; an increasing trend may indicate worsening tamponade or impending respiratory failure in severe COPD.

• Aggressive respiratory therapy (chest physiotherapy) may avert need for intubation in pulmonary disease.

Patient counseling

• Educate COPD patients on self-care: pursed-lip breathing, diaphragmatic exercises, coughing, deep breathing.

• Emphasize adherence to prescribed medications and awareness of adverse effects.

Pediatric pointers

• Pulsus paradoxus occurs in children with chronic pulmonary disease, especially during acute asthma attacks.

• Children with pericarditis may develop paradoxus due to cardiac tamponade, although it is more common in adults.

• A drop >20 mm Hg is a reliable indicator of tamponade in children; 10–20 mm Hg is equivocal.

References

1. Buttaro TM, Tybulski J, Bailey PP, Sandberg-Cook J. Primary care: A collaborative practice. St. Louis (MO): Mosby Elsevier; 2008. p.444–447.

2. McCance KL, Huether SE, Brashers VL, Rote NS. Pathophysiology: The biologic basis for disease in adults and children. Maryland Heights (MO): Mosby Elsevier; 2010.

3. Sommers MS, Brunner LS. Pocket diseases. Philadelphia (PA): F.A. Davis; 2012.

4. Goldberger ZD, Bonow RO, Mann DL, Zipes DP. Braunwald’s heart disease: A textbook of cardiovascular medicine. 12th ed. Philadelphia (PA): Elsevier; 2021.

5. Otto CM. Textbook of clinical echocardiography. 6th ed. Philadelphia (PA): Elsevier; 2018.