Cardiac Tamponade

KEY FEATURES

ESSENTIALS OF DIAGNOSIS

• Increased jugular venous pressure with an obliterated y descent

• Pulsus paradoxus

• Echocardiographic evidence of right atrial and ventricular collapse

• Equal diastolic pressures in all 4 cardiac chambers

GENERAL CONSIDERATIONS

• Cardiac tamponade occurs when the intrapericardial pressure exceeds the intracardiac pressures and causes cardiac chamber collapse, poor diastolic filling, and reduced cardiac output.

• The volume of pericardial fluid required to cause tamponade depends on the speed of fluid accumulation

• Severe tamponade may ensue with a modest effusion (as in the setting of trauma) in a brief time

• Low-pressure cardiac tamponade occurs when an effusion that is ordinarily insufficient to cause hemodynamic compromise becomes significant when intravascular volume is depleted. This typically occurs in patients with hypovolemia and severe systemic diseases, hemorrhage, or cancer, or in patients with hypovolemia after diuresis

CLINICAL PRESENTATION

SYMPTOMS AND SIGNS

• Dyspnea or tachypnea

• Chest discomfort

• Impaired consciousness

• Signs of reduced cardiac output and shock

PHYSICAL EXAM FINDINGS

• Hypotension

• Diminished pulse pressure

• Tachycardia until the terminal stages, when bradycardia ensues

• Pulsus paradoxus, which is conventionally defined as an inspiratory systolic fall in systemic arterial pressure of 10 mm Hg or more

• Elevated jugular venous pressure with blunted or obliterated y descent

• Diminished heart sounds

• Rarely, a pericardial rub

DIFFERENTIAL DIAGNOSIS

• Cardiogenic shock

• Severe obstructive airway disease

• Congestive heart failure

• Pulmonary embolus

• Constrictive pericarditis

• Tension pneumothorax

DIAGNOSTIC EVALUATION

LABORATORY TESTS

• Fluid obtained at pericardial drainage should be examined using the following tests:

  • – Gram’s stain

  • – Bacterial cultures

  • – Acid-fast bacilli stain and culture

  • – Polymerase chain reaction

  • – Cytology and carcinoembryonic antigen (CEA)

ELECTROCARDIOGRAPHY

• Low-voltage QRS complex

• Electrical alternans with large effusions

IMAGING STUDIES

• Chest x-ray findings:

  • – Enlarged cardiac silhouette

  • – Lung fields frequently oligemic

• Echocardiography, an invaluable adjunctive tool:

  • – Confirms the presence of pericardial fluid

  • – Provides evidence of increased intrapericardial pressure such as diastolic collapse of the right atrium and right ventricle

• Two-dimensional echo is helpful in guiding pericardiocentesis

DIAGNOSTIC PROCEDURES

• Cardiac catheterization findings:

  • – Elevated and equal or near-equal diastolic pressures in all 4 cardiac chambers

  • – Loss of the normal y descent in atrial pressure tracings

  • – Reduced cardiac output

TREATMENT

CARDIOLOGY REFERRAL

• In-hospital emergent referral is indicated in patients with suspected cardiac tamponade for urgent pericardiocentesis

HOSPITALIZATION CRITERIA

• Suspected cardiac tamponade

MEDICATIONS

• IV fluids until drainage can be accomplished

  ...