Cardiac Tamponade

1. Definitions
   1. Compression of heart by fluid in pericardial sac
2. Pathophysiology
   1. Physiologic effects of effusion vary by timing
      1. Gradual accumulation is accomodated by sack stretch (up to 250 ml)
      2. Rapid accumulation results in compromise
   2. Cardiac Tamponade pathway
      1. Effusion prevents diastolic relaxation of ventricles
      2. Right Ventricular Filling Pressure approaches left ventricular pressure
         1. Loss of normal pressure differentials prevents diastolic filling of heart
3. Causes
   1. See Pericardial Effusion
4. Symptoms
   1. Common
      1. Dyspnea
      2. Fatigue
   2. Other symptoms
      1. Orthopnea
      2. Chest Pain
      3. Syncope
5. Signs
   1. Classic presentation (Beck's Triad)
      1. Hypotension
      2. Narrow Pulse Pressure
      3. Quiet heart sounds
   2. Cardiac exam
      1. Distended neck veins (Jugular Venous Distention)
         1. Increased Central Venous Pressure (CVP)
      2. Hyperdynamic JVP waveform (exaggerated X descent)
      3. Pulsus Paradoxus (pathognomonic for Pericardial Effusion)
      4. Faint heart sounds
      5. Friction rub
   3. Cardiopulmonary Shock
      1. Kussmaul's Sign
      2. Cold clammy skin
      3. Tachycardia
      4. Falling arterial pressure
         1. Narrow Pulse Pressure
         2. Hypotension
      5. Cyanosis
6. Imaging: Chest XRay
   1. Enlarged cardiac shadow: Globular appearance
7. Diagnostics
   1. Echocardiogram (preferred study)
      1. Focused Assessment with Sonography for Trauma (FAST)
      2. See Pericardial Effusion for Echocardiogram findings
   2. Electrocardiogram
      1. Low voltage complexes
      2. Electrical alternans may be present
      3. Untreated, Pulseless Electrical Activity (PEA) may result
   3. Cardiac catheterization: Right-Left pressures equal
      1. Right ventricular diastolic pressure
      2. Pulmonary capillary wedge pressure
8. Diagnosis
   1. Pulsus Paradoxus with Pericardial Effusion confirms diagnosis
9. Differential Diagnosis: Shock states
   1. Myocardial Infarction
   2. Septic Shock
   3. Pulmonary Embolism
10. Management: Emergent
    1. Immediate Pericardiocentesis under Ultrasound guidance (ATLS)
       1. See Emergency Pericardiocentesis
       2. Sub-xiphoid approach
       3. Needle angled toward left Shoulder
       4. Constant suction applied to syringe on entry
       5. Send fluid for cytology if not Traumatic in origin
    2. Emergency Thoracotomy
       1. Indicated in Cardiac Tamponade due to Trauma (esp penetrating), refractory to Pericardiocentesis
    3. Emergent Cardiothoracic surgery
       1. Pericardial window placement and other definitive management
    4. Intravenous Fluids
       1. Transient stabilization to increase venous pressure
    5. Precautions
       1. Avoid Positive Pressure Ventilation until after decompression with Pericardiocentesis
          1. Negative intrathoracic pressure is the last safeguard maintaining venous return in Pericardial Tamponade
          2. Positive Pressure Ventilation eliminates negative intrathoracic pressure
          3. Pulseless Electrical Activity arrest (PEA arrest) results
       2. Avoid measures that reduce cardiac filling
          1. Avoid inotropes (increased Heart Rate decreases filling time)
       3. References
          1. Mallemat and Swadron in Herbert (2013) EM:Rap 13(12): 10-11
11. Management: Malignancy specific
    1. Consider reaccumulation prevention (post-stabilization)
       1. Chemotherapy
       2. Radiation
       3. Sclerosis