Chapter 93. Tamponade

• Occurs when fluid or clots accumulate rapidly in the pericardial space, decreasing pericardial compliance; a large amount of pericardial fluid can accumulate over an extended period of time without causing tamponade
  • Ventricular compliance is decreased, leading to decreased diastolic filling and decreased stroke volume
  • Systemic venous return is impaired and as RA and RV collapse occurs, blood accumulates in the venous circulation, which further decreases cardiac output and venous return
  • In the extreme, pressures equalize in all heart cavities, with no blood flow
• Compensatory mechanisms:
  • Tachycardia to maintain cardiac output
  • Increased vascular resistance to maintain BP
  • Spontaneous ventilation, by decreasing intrathoracic pressure on inspiration, facilitates RV filling and ejection
• Three phases of hemodynamic changes
  • Phase I: Increased stiffness of ventricle due to pericardial fluid accumulation, requiring a higher filling pressure (LV and RV filling pressures >intrapericardial pressure)
  • Phase II: Pericardial pressure increases above ventricular filling pressure, resulting in decreased cardiac output
  • Phase III: Cardiac output decreases even more because of equilibration of pericardial and LV filling pressures
• Medical emergency, needs to be treated immediately to avoid death
• Any acute hemodynamic deterioration in a patient post cardiac surgery should lead to an emergent re-exploration, unless another obvious cause is present

Symptoms include

• Dyspnea, tachypnea; patient typically sitting
• Tachycardia
• Peripheral hypoperfusion with oliguria
• Pulsus paradoxus, with decreased pulse amplitude on inspiration
• Beck’s triad: increased jugular venous pressure, hypotension, and diminished heart sounds

Echocardiogram: best diagnostic tool.

• There can be a circumferential fluid collection, or sometimes a single clot compressing the RA
• Right heart compression
• Interventricular septum flattening (RV impairing LV filling)

CXR: cardiomegaly, water-bottle-shaped heart, or pericardial calcifications; often normal 12-lead EKG findings suggestive of pericardial tamponade:

• Sinus tachycardia
• Low-voltage QRS complexes
• Electrical alternans (very specific but rare)
• PR depression in all leads

If the patient has a pulmonary artery catheter (PAC) (no indication to insert a PAC emergently)

• Low CO
• Equalization of CVP = RVEDP = PAP (diastolic)

• Hemodynamic collapse
  • Emergent drainage at the bedside, ideally ultrasound-guided needle drainage (usually removing 100–200 mL of fluid is sufficient to relieve hemodynamic signs and symptoms)
  • Sternotomy re-exploration at bedside if post cardiac surgery
• If less critically ill, or after emergent drainage, a pericardial window or sclerosing of the pericardium can be performed surgically
• Supplemental oxygen
• Volume expansion to maintain preload
• Inotropic drugs can be useful to increase CO without increasing SVR (see Table 93-2)
• Avoid positive pressure ventilation because of the associated decrease in venous return; keep patient breathing spontaneously
• Repeat the echocardiogram and CXR within 24 hours

Anesthesia for pericardial window

• PreOp
  • Assess patient and stabilize hemodynamic status with goals of maintaining HR, preload, and afterload (i.e., fast, full, and tight) by giving crystalloids and using inotropes
  • Consider placing arterial line and PAC
  • Discuss type of procedure with surgeon and what depth of ...