What is the protocol for weaning a patient from Veno-Venous (VV) Extracorporeal Membrane Oxygenation (ECMO)?

VV ECMO Weaning Protocol

The American Thoracic Society recommends a systematic, protocol-driven approach to VV ECMO weaning, which involves gradually reducing extracorporeal support while monitoring for signs of native lung recovery to minimize mortality and morbidity. 1

Prerequisites for Initiating Weaning

Before starting the weaning process, ensure:

• Improvement in underlying lung pathology
• Adequate oxygenation parameters
• Acceptable ventilator settings
• Hemodynamic stability
• Resolution of severe acidosis 1

Systematic Weaning Process

Step 1: Reduce ECMO Blood Flow Rate (EBFR)

• Decrease by 0.5-1 L/min increments
• Monitor SpO2, hemodynamics, and work of breathing
• Target minimum flow of 2 L/min before considering complete removal 1

Step 2: Reduce Sweep Gas Flow Rate (SGFR)

• After optimizing EBFR, gradually decrease sweep gas flow by 0.5-1 L/min
• Monitor PaCO2 and pH closely during this process 1

Step 3: Reduce FdO2 on ECMO Circuit

• Decrease the fraction of delivered oxygen on the ECMO circuit
• Target FdO2 of 0.21 (room air) before discontinuation 1

Criteria for ECMO Removal

ECMO can be removed when the following criteria are met:

• Successful trial off with PaO2/FiO2 >150-200 on moderate ventilator settings
• PaCO2 <50 mmHg with acceptable pH (>7.30)
• No significant increase in work of breathing
• Hemodynamic stability
• Acceptable ventilator parameters:
  • FiO2 ≤0.5
  • PEEP ≤10 cmH2O
  • Plateau pressure ≤30 cmH2O 1

Post-ECMO Removal Care

After ECMO removal:

• Continue lung-protective ventilation strategies
• Gradually wean from mechanical ventilation
• Monitor for bleeding complications related to acquired von Willebrand syndrome (AVWS)
  • AVWS typically resolves within 24 hours after ECMO removal 2, 1
• Maintain vigilant monitoring for signs of respiratory deterioration 1

Important Considerations

Acquired von Willebrand Syndrome

• Almost all ECMO patients develop partial or complete loss of VWF high-molecular-weight multimers within hours of device implantation
• This condition persists throughout ECMO support
• VWF multimer distribution returns to normal within 12-24 hours after weaning from ECMO 2

Timing Considerations

• Weaning should only be attempted after clear evidence of lung recovery
• Prolonged ECMO duration is associated with higher mortality after weaning 3
• The weaning process should be gradual to avoid respiratory decompensation

Common Pitfalls to Avoid

• Weaning too early before adequate lung recovery
• Weaning too rapidly without allowing time to assess patient tolerance
• Failure to monitor both gas exchange and work of breathing during the weaning process
• Not considering the resolution of AVWS when planning post-ECMO care (typically resolves within 24 hours after ECMO removal) 2, 1