What are the causes of sudden cardiac arrest post-Extracorporeal Membrane Oxygenation (ECMO)?

Causes of Sudden Cardiac Arrest Post-ECMO

The primary causes of sudden cardiac arrest following ECMO support include left ventricular distension, acquired von Willebrand syndrome leading to bleeding complications, electrolyte abnormalities, pulmonary embolism, and coronary thrombosis. 1

Cardiovascular Causes

• Left Ventricular Distension: Peripheral VA-ECMO increases LV afterload, which can lead to LV distension, ventricular stasis, pulmonary congestion, and myocardial ischemia if not properly managed 1
• Coronary Ischemia: Inadequate coronary perfusion during or after ECMO can lead to myocardial ischemia and subsequent cardiac arrest, especially in patients with underlying coronary artery disease 1
• Harlequin Syndrome: Differential upper and lower torso oxygenation (North-South syndrome) occurs in approximately 10% of peripherally cannulated patients, leading to inadequate oxygenation of coronary and cerebral circulation 1
• Arrhythmias: Electrolyte imbalances, myocardial injury, and ischemia during ECMO can trigger life-threatening arrhythmias 2

Bleeding Complications

• Acquired von Willebrand Syndrome (AVWS): Almost all ECMO patients develop partial or complete loss of VWF high-molecular-weight multimers within hours of device implantation, leading to bleeding diathesis 1
• Intracranial Hemorrhage: Early head CT can show intracranial hemorrhage in up to 11% of patients within 24 hours of ECPR, which can lead to neurological deterioration and cardiac arrest 1
• Major Bleeding: Bleeding complications occur in 45.1% of VV-ECMO patients and 62.1% of VA-ECMO patients, with intracranial hemorrhage associated with the highest mortality rates 1

Metabolic and Electrolyte Disturbances

• Hypokalemia: Severe hypokalemia can trigger cardiac arrest and may require aggressive potassium repletion 3
• Acid-Base Disorders: Metabolic acidosis or severe alkalosis can precipitate cardiac arrest post-ECMO 1
• Hypoxemia: Inadequate oxygenation, particularly in patients with Harlequin syndrome, can lead to myocardial hypoxia and cardiac arrest 1

Thromboembolic Events

• Pulmonary Embolism: Thrombotic complications occur in 25.3% of VV-ECMO patients and 20% of VA-ECMO patients, with pulmonary embolism being a potentially fatal complication 1, 4
• Coronary Thrombosis: Thrombus formation in the ECMO circuit can lead to coronary embolism and subsequent cardiac arrest 5
• Circuit Thrombosis: Despite anticoagulation, clot formation in the ECMO circuit can occur and lead to circuit failure and hemodynamic collapse 1

Mechanical Complications

• Cannula Dislodgement: Accidental dislodgement of ECMO cannulas can cause rapid hemodynamic collapse and cardiac arrest 2
• Circuit Failure: Oxygenator failure, pump malfunction, or tubing rupture can lead to sudden cessation of circulatory support 2
• Inadequate ECMO Flow: Suboptimal ECMO flow rates can result in inadequate end-organ perfusion and cardiac arrest 1

Management Considerations

• Point-of-Care Ultrasound (POCUS): Should be performed immediately to identify potentially reversible causes of cardiac arrest, such as cardiac tamponade, pulmonary embolism, or LV distension 5
• LV Unloading: Consider implementing LV unloading strategies such as intra-aortic balloon pump (IABP), Impella, or direct LV venting to prevent distension and improve outcomes 1
• Electrolyte Monitoring: Regular monitoring and correction of electrolytes, particularly potassium, is essential to prevent arrhythmias and cardiac arrest 3
• Bleeding Management: Recognize and address AVWS-related bleeding promptly, as bleeding complications are associated with high mortality rates 1
• Re-initiation of ECMO: Consider rapid re-initiation of ECMO (ECPR) for patients with refractory cardiac arrest despite conventional resuscitation 6

Prevention Strategies

• Optimal Mean Arterial Pressure: Maintain MAP that provides adequate cerebral and end-organ perfusion while minimizing LV afterload 1
• Proper Ventilation Strategy: Implement lung-protective ventilation strategies and maintain adequate oxygenation to prevent Harlequin syndrome 1
• Anticoagulation Management: Balance the risk of thrombosis and bleeding by carefully monitoring anticoagulation parameters 1
• Early Coronary Revascularization: Consider early coronary revascularization in patients with ischemic cardiac arrest, as it improves outcomes 1
• Fluid Balance: Strive for a daily negative fluid balance after ECMO flows are optimized and the patient is hemodynamically stable 1

Understanding these causes and implementing appropriate preventive and management strategies can significantly improve outcomes in patients experiencing cardiac arrest following ECMO support.