II. Definitions
- Cardiac Tamponade
- Compression of heart by fluid in pericardial sac resulting in hemodynamic instability
III. Pathophysiology
- Physiologic effects of effusion vary by timing
- Gradual accumulation is accomodated by sack stretch (up to 250 ml)
- Rapid accumulation results in more abrupt hemodynamic compromise
- Cardiac Tamponade pathway
- Effusion prevents diastolic relaxation of ventricles
- Right Ventricular Filling Pressure approaches left ventricular pressure
- Loss of normal pressure differentials prevents diastolic filling of heart
IV. Causes
V. Symptoms
- Common
- Other symptoms
VI. Signs
- Classic presentation (Beck's Triad)
- Hypotension
- Narrow Pulse Pressure
- Quiet or muffled heart sounds
- Cardiac exam
- Distended neck veins (Jugular Venous Distention)
- Increased Central Venous Pressure (CVP)
- Hyperdynamic JVP waveform (exaggerated X descent)
- Pulsus Paradoxus (pathognomonic for Pericardial Effusion)
- Faint heart sounds
- Friction rub
- Distended neck veins (Jugular Venous Distention)
- Cardiopulmonary Shock
- Kussmaul's Sign
- Cold clammy skin
- Tachycardia
- Falling arterial pressure
- Cyanosis
VII. Imaging: Chest XRay
- Enlarged cardiac shadow: Globular appearance
VIII. Diagnostics
-
Echocardiogram (preferred study)
- Focused Assessment with Sonography for Trauma (FAST)
- See Pericardial Effusion
- Right heart wall movement appears as a paradoxical rocking motion
- Right atrium collapse in systole (also occurs with Hypovolemic Shock)
- Right ventricular collapse of free wall in diastole (despite tricuspid valve opening, and RV filling)
- Inferior Vena Cava
- Does not collapse during inspiration when Cardiac Tamponade is present
-
Electrocardiogram
- Low voltage complexes
- Electrical alternans may be present
- Untreated, Pulseless Electrical Activity (PEA) may result
- Cardiac catheterization: Right-Left pressures equal
- Right ventricular diastolic pressure
- Pulmonary capillary wedge pressure
IX. Diagnosis
-
Bedside Ultrasound (see Echocardiogram above)
- Consider Bedside Ultrasound in all patients with Tachypnea, Shortness of Breath or Tachycardia
- Beck's Triad has low sensitivity (not all Cardiac Tamponade patients have Hypotension)
- Pulsus Paradoxus with Pericardial Effusion confirms diagnosis
X. Differential Diagnosis: Shock states
XI. Management: Emergent
- Immediate Pericardiocentesis under Ultrasound guidance (ATLS)
- See Emergency Pericardiocentesis
- Hypoperfusion with Cardiac Tamponade is an indication for Pericardiocentesis
- Sub-xiphoid approach with needle angled toward left Shoulder
- Parasternal approach has been advocated due to clear path to Pericardium
- Constant suction applied to syringe on entry
- Send fluid for cytology if not Traumatic in origin
-
Emergency Thoracotomy
- Indicated in Cardiac Tamponade due to Trauma (esp penetrating), refractory to Pericardiocentesis
- Emergent Cardiothoracic surgery
- Pericardial window placement and other definitive management
-
Intravenous Fluids
- Transient stabilization to increase venous pressure
- Norepinephrine may also be used to transiently improve perfusion
- Precautions
- Avoid Positive Pressure Ventilation until after decompression with Pericardiocentesis
- Negative intrathoracic pressure is the last safeguard maintaining venous return in Pericardial Tamponade
- Positive Pressure Ventilation eliminates negative intrathoracic pressure
- Pulseless Electrical Activity arrest (PEA arrest) results
- Avoid measures that reduce cardiac filling
- Avoid inotropes (increased Heart Rate decreases filling time)
- References
- Mallemat and Swadron in Herbert (2013) EM:Rap 13(12): 10-11
- Avoid Positive Pressure Ventilation until after decompression with Pericardiocentesis
XII. Management: Malignancy specific
- Consider reaccumulation prevention (post-stabilization)
- Chemotherapy
- Radiation
- Sclerosis