VA ECMO Weaning Protocol
VA ECMO weaning should follow a systematic, protocol-driven approach with gradual reduction of support while monitoring for cardiac recovery to minimize mortality and morbidity. 1, 2
Pre-Weaning Assessment
Before initiating weaning, ensure:
- Evidence of cardiac recovery with improved left ventricular function
- Hemodynamic stability with minimal vasopressor/inotropic support
- Resolution of the underlying condition that necessitated ECMO
- Adequate end-organ perfusion and function
- Resolution of severe acidosis
Weaning Process Algorithm
Step 1: Echocardiographic and Hemodynamic Assessment
- Perform comprehensive echocardiography to assess:
- Left ventricular ejection fraction (LVEF)
- Right ventricular function
- Valve function
- Volume status
- Monitor pulse pressure - increasing pulse pressure indicates improving cardiac function 3
- Consider hemodynamic transesophageal echocardiography (hTEE) for continuous monitoring during weaning 4
Step 2: Reduce ECMO Flow
- Gradually decrease ECMO blood flow rate by 0.5-1 L/min increments
- Monitor:
- Mean arterial pressure (MAP) - maintain adequate cerebral and end-organ perfusion
- Pulse pressure - widening indicates improved cardiac function
- Echocardiographic parameters for ventricular function
- Arterial blood gases from right radial artery (best represents cerebral perfusion) 1
- Target minimum flow of 2 L/min before considering complete removal
Step 3: Adjust Inotropic Support
- Titrate inotropic support as needed during flow reduction
- Norepinephrine is preferred over epinephrine (epinephrine alone is associated with higher mortality) 1
- Target inotropic score of approximately 10 (reduced from pre-ECMO levels) 3
Step 4: Trial Off Period
- Once at minimum ECMO flow, conduct a trial off period (30-60 minutes)
- Assess for:
- Adequate cardiac output
- Stable hemodynamics without significant increase in inotropes
- Acceptable arterial blood gases
- No signs of left ventricular distension
Step 5: Decannulation
- If trial off is successful, proceed with decannulation
- Continue monitoring for 24-48 hours post-decannulation
Post-ECMO Monitoring
- Monitor for acquired von Willebrand syndrome (AVWS), which typically resolves within 12-24 hours after ECMO removal 1, 5
- Continue appropriate inotropic support as needed
- Maintain lung-protective ventilation strategies
- Monitor for signs of cardiac deterioration
Special Considerations
Left Ventricular Distension
- VA ECMO increases LV afterload, which can negatively impact cardiac recovery
- Consider LV unloading strategies during weaning if distension occurs:
Harlequin Syndrome (North-South Syndrome)
- Monitor for differential oxygenation between upper and lower body
- Management options:
- Increase ECMO flow to move mixing point proximally
- Optimize ventilator settings
- Consider V-AV ECMO configuration if persistent 1
Predictors of Poor Weaning Outcomes
- Longer ECMO duration (>7 days) 3
- Persistent right ventricular dysfunction 3
- Need for continuous renal replacement therapy 3
- High inotropic requirements during weaning 3
- Significant bleeding complications requiring multiple transfusions 3
Pitfalls to Avoid
- Weaning too rapidly without adequate assessment of cardiac function
- Failure to recognize persistent RV dysfunction (occurs in approximately 21% of weaned patients) 3
- Inadequate monitoring of arterial blood gases from the right radial artery
- Overlooking the need for LV unloading strategies during weaning
- Premature discontinuation of monitoring after decannulation
Remember that successful weaning is a multifactorial process requiring sufficient recovery of both myocardial and end-organ function, with LVEF often remaining somewhat impaired (typically around 35%) even at successful weaning 3.