What are the guidelines for Cardiovascular (CV) Extracorporeal Membrane Oxygenation (ECMO) cannulation?

Guidelines for Cardiovascular ECMO Cannulation

The most common and recommended cannulation strategy for cardiovascular ECMO is peripheral cannulation with femoral venous drainage and outflow to the femoral artery, which should be performed using the Seldinger technique with ultrasound guidance. 1

Cannulation Approaches

Peripheral Cannulation (Primary Approach)

• Femoral-Femoral Configuration:

  • Venous cannula: Femoral vein for drainage
  • Arterial cannula: Femoral artery for return
  • Target ECMO flow: 3-4 L/min immediately after cannulation 1
  • Technique: Percutaneous Seldinger technique with ultrasound guidance 2

• Critical Considerations:

  • Distal perfusion catheter (DPC) should be placed in the superficial femoral artery at the time of initial cannulation to prevent limb ischemia 3
  • Monitor for Harlequin syndrome (North-South syndrome) which occurs in approximately 10% of peripherally cannulated patients 1
  • Right radial arterial line placement is essential for monitoring cerebral perfusion 1

Alternative Cannulation Sites

• Axillary Approach:

  • Indicated when femoral access is contraindicated (critical lower extremity ischemia, trauma, infection) 4

• Advanced Configurations:

  • V-AV ECMO: Additional oxygenated return cannula in jugular vein to address Harlequin syndrome 1
  • For severe respiratory failure with VA ECMO: Consider dual circulation management strategies 1

Monitoring Parameters During Cannulation

Hemodynamic Targets

• Arteriovenous O₂ difference: Maintain between 3-5 cc O₂/100ml blood 1
• Mixed venous saturation (SvO₂): Target above 66% 1
• Mean arterial pressure (MAP): Individualize to provide adequate cerebral and end-organ perfusion while minimizing LV afterload 1

Neurological Monitoring

• Pupillary assessment and pupillometry if available 1
• Consider continuous cerebral regional oxygen saturation (rSO₂) monitoring, especially with peripheral VA ECMO 1
• Early neuroimaging if risk of acute brain injury based on neuromonitoring 1

Left Ventricular Management During Cannulation

LV Unloading Strategies

• Upon VA ECMO cannulation, assess for LV distension which can impair cardiac recovery 1
• LV unloading options (in order of increasing invasiveness):
  1. Inotropic support (norepinephrine preferred over epinephrine) 1
  2. Intra-aortic balloon pump (IABP)
  3. Impella device
  4. Pulmonary artery venting via internal jugular vein
  5. Atrial septostomy
  6. Direct LV apical cannulation 1

Special Cannulation Scenarios

ECPR (Extracorporeal Cardiopulmonary Resuscitation)

• Rapid femoral-femoral cannulation is recommended 1
• Consider mild-moderate hypothermia (33-36°C) after cannulation 1
• Avoid arterial hypoxemia (PaO₂ < 70 mmHg) for 24-48 hours post-cannulation 1

Pulmonary Embolism

• For massive PE with cardiogenic shock, VA ECMO can be used as a bridge to surgical embolectomy or catheter-directed treatment 1
• Cannulation should be performed before hemodynamic collapse 1

Post-Cannulation Management

Immediate Post-Cannulation Care

• Discontinue mechanical chest compressions after successful cannulation 1
• Wean vasoactive inotropic support as tolerated 1
• Perform serial arterial blood gas sampling in the first 24 hours 1
• Monitor for differential hypoxia and adjust ECMO flow accordingly 1

Weaning Considerations

• Assess for cardiac recovery indicators before initiating weaning:
  • Improved pulse pressure
  • Reduced inotropic requirements
  • Improved left ventricular ejection fraction
  • Resolution of the underlying condition 5
• Gradually reduce ECMO blood flow by 0.5-1 L/min increments while monitoring hemodynamic parameters 5

Complications and Pitfalls

Vascular Complications

• Limb ischemia: Occurs in up to 22.7% of patients without initial distal perfusion catheter 3
• Bleeding: Common at cannulation sites due to required anticoagulation
• Vessel injury: Dissection, perforation, or erroneous cannulation 6

Neurological Complications

• Avoid rapid early decrease in PaCO₂ during cannulation as it's associated with increased risk of intracranial hemorrhage 1
• Monitor for signs of cerebral venous sinus thrombosis which may require endovascular intervention in deteriorating patients 1

By following these guidelines for cardiovascular ECMO cannulation, clinicians can optimize patient outcomes while minimizing complications associated with this life-saving intervention.