What is the management of cardiac arrest due to pulmonary embolism?

Management of Cardiac Arrest Due to Pulmonary Embolism

Fibrinolytic therapy should be considered when pulmonary embolism is suspected as the cause of cardiac arrest, as it may improve return of spontaneous circulation and survival. 1

Initial Management

1. Recognition and Diagnosis

   • Consider PE as cause when cardiac arrest presents with:
     • Pulseless electrical activity (PEA) - most common initial rhythm (63%) 2
     • Asystole (32%) 2
     • History of immobility, recent surgery, cancer, or other risk factors for PE
   • If available during resuscitation, use bedside echocardiography to:
     • Identify right ventricular dilation/dysfunction
     • Rule out other causes (cardiac tamponade, severe hypovolemia)
     • Support clinical suspicion of PE 1, 3

2. Immediate Resuscitation Measures

   • Provide high-quality CPR according to standard protocols
   • Avoid routine hyperventilation as it may worsen cerebral ischemia 1
   • Maintain normocapnia (PaCO2 40-45 mmHg or PETCO2 35-40 mmHg) 1
   • Consider fibrinolytic therapy early if PE is suspected 1

Specific Interventions for PE-Related Cardiac Arrest

Fibrinolytic Therapy

• Indication: When PE is suspected as cause of cardiac arrest 1
• Timing: Consider early administration during CPR 2
• Agent options:
  • Alteplase (tPA): 100 mg IV bolus or infusion over 2 hours 3, 4
  • Tenecteplase: Weight-based dosing (alternative option) 5
• Expected outcomes:
  • Higher rates of return of spontaneous circulation (81% vs 43% compared to no thrombolysis) 2
  • Overall survival remains low (10-13.6%) but better than without intervention 6, 2
• Important considerations:
  • CPR itself is not an absolute contraindication to thrombolysis 1
  • Relative contraindications may become less relevant in immediately life-threatening situations 1
  • Bleeding risk exists but may be acceptable given the high mortality of untreated PE-related arrest 6

Alternative Interventions (if thrombolysis contraindicated or failed)

1. Percutaneous mechanical thrombectomy:

   • Consider in patients who are not candidates for fibrinolytic therapy 1
   • May restore pulmonary perfusion in majority of cases (85.7%) 1
   • Can be performed with VA-ECMO support for hemodynamic stability 7

2. Surgical embolectomy:

   • Generally avoid in patients who have received CPR due to high mortality 1
   • Consider only in select cases with surgical expertise immediately available

3. Venoarterial ECMO:

   • Can provide circulatory support during catheter-based interventions 7
   • Allows time for definitive treatment in refractory cases

Post-Resuscitation Care (if ROSC achieved)

1. Anticoagulation:

   • Initiate heparin therapy once ROSC is achieved 8
   • Unfractionated heparin: 80 units/kg bolus followed by 18 units/kg/hour infusion 3
   • Monitor aPTT (target 1.5-2 times normal) 8

2. Ventilation management:

   • Avoid hyperventilation (may worsen cerebral ischemia) 1
   • Use tidal volumes of 6-8 mL/kg predicted body weight 1
   • Target normocapnia (PaCO2 40-45 mmHg) 1

3. Hemodynamic support:

   • Titrate vasopressors/inotropes to optimize organ perfusion 1
   • Consider IV fluids as part of post-arrest care 1

4. Targeted temperature management:

   • Consider therapeutic hypothermia if patient remains comatose 1

Pitfalls and Caveats

• Delayed recognition: PE is often diagnosed only post-mortem (30% of cases) 2 - maintain high index of suspicion
• Withholding thrombolysis: Given the extremely high mortality of PE-related arrest (90%), the benefit of thrombolysis likely outweighs bleeding risk in most cases 4, 2
• Surgical embolectomy after CPR: Avoid this approach due to very high mortality 1
• Prolonged CPR: Metabolic acidosis is often severe in PE-related arrest (median pH 6.95) 2, but should not deter aggressive management including thrombolysis

Remember that early recognition and prompt intervention with fibrinolytic therapy offer the best chance of survival in this otherwise highly fatal condition.