What is the management of pulmonary embolism (PE) leading to cardiac arrest?

Management of Pulmonary Embolism in Cardiac Arrest

In patients with confirmed PE as the precipitant of cardiac arrest, thrombolysis, surgical embolectomy, and mechanical embolectomy are all reasonable emergency treatment options, with thrombolysis being the most widely available and rapidly implementable intervention. 1

Initial Management and Diagnosis

• Consider PE as the cause of cardiac arrest when:

  • Presenting rhythm is pulseless electrical activity (PEA) (36-53% of PE-related arrests) 1
  • Patient has risk factors: immobility, recent surgery, cancer, history of VTE
  • Sudden onset of symptoms prior to arrest

• Use bedside echocardiography during CPR to identify:

  • Right ventricular dilation/dysfunction
  • Presence of right heart thrombi
  • Rule out other causes of arrest 2

Immediate Interventions

1. Continue high-quality CPR according to standard protocols

   • Maintain normocapnia (PaCO2 40-45 mmHg)
   • Avoid hyperventilation which may worsen right heart strain 2

2. Administer thrombolytic therapy early

   • Do not delay while awaiting definitive diagnosis if suspicion is high
   • CPR is NOT a contraindication to thrombolysis 1, 2
   • Early administration improves outcomes compared to use after failure of conventional ACLS 1

Thrombolytic Options

For Confirmed PE:

• Alteplase (tPA) options:

  • 100 mg over 2 hours (standard dosing) 3
  • Accelerated dosing: 50 mg IV bolus with option for repeat bolus in 15 minutes 1

• Tenecteplase: Single-dose weight-based administration 1, 4

For Suspected PE:

• Thrombolysis may be considered when cardiac arrest is suspected to be caused by PE (Class IIb, LOE C-LD) 1
• Given poor outcomes (65-90% mortality) associated with fulminant PE without clot-directed therapy, standard contraindications to thrombolysis may be superseded 1

Alternative Interventions

Surgical Embolectomy:

• Consider for patients with contraindications to thrombolysis or failed thrombolysis 1, 2
• Requires rapid transfer to operating room and cardiopulmonary bypass
• Perioperative mortality rates of 6% or less have been reported with rapid multidisciplinary approach 1
• Avoid in patients who have received prolonged CPR due to high mortality 2

Percutaneous Catheter-Directed Treatment:

• Options include:
  • Thrombus fragmentation with pigtail or balloon catheter
  • Rheolytic thrombectomy
  • Suction thrombectomy
  • Rotational thrombectomy 1
• Consider when thrombolysis is contraindicated or has failed 2

Post-ROSC Management

1. Initiate anticoagulation:

   • Unfractionated heparin: 80 units/kg bolus followed by 18 units/kg/hour infusion 2
   • LMWH or fondaparinux preferred over UFH when patient is stable 2

2. Hemodynamic support:

   • Titrate vasopressors/inotropes to optimize organ perfusion
   • Consider IV fluids cautiously (may worsen RV strain) 2

3. Ventilation management:

   • Target normocapnia (PaCO2 40-45 mmHg)
   • Use tidal volumes of 6-8 mL/kg predicted body weight 2

4. Consider targeted temperature management if patient remains comatose 2

Outcomes and Prognosis

• Recent systematic review shows thrombolysis is associated with increased ROSC but not necessarily improved survival to hospital discharge 5
• Survival rates remain low, with one study showing only 13.6% survival to hospital discharge despite 50% achieving ROSC 6
• Early intervention is critical, as outcomes deteriorate with prolonged cardiac arrest 7, 8

Pitfalls and Caveats

• Diagnostic challenges: PE is difficult to diagnose during cardiac arrest and may be missed in up to 84% of cases 7
• Bleeding risk: While bleeding is a concern with thrombolysis during CPR, the risk of major bleeding appears to be acceptable given the high mortality of untreated PE-related cardiac arrest 5, 8
• Dosing uncertainty: No consensus exists on ideal thrombolytic dosing in PE-associated cardiac arrest 1, 6
• Treatment delay: Waiting for definitive diagnosis before initiating thrombolysis may result in worse outcomes 1, 7

Remember that PE-related cardiac arrest has extremely high mortality, and prompt intervention with thrombolytic therapy, even during ongoing CPR, may be life-saving when PE is the suspected cause.