What scores are used to determine eligibility for Extracorporeal Membrane Oxygenation (ECMO) initiation?

Scores for ECMO Initiation

The SAVE (Survival After Veno-arterial ECMO) score is the primary validated scoring system for predicting survival in patients receiving ECMO for refractory cardiogenic shock, while the Oxygenation Index (OI) is the key metric for determining ECMO candidacy in neonatal and pediatric respiratory failure. 1

Primary Scoring Systems

SAVE Score for Cardiogenic Shock

• The SAVE score specifically predicts survival for patients receiving VA-ECMO for refractory cardiogenic shock and should guide decision-making in adult cardiac failure cases 1
• This score helps determine which patients are most likely to benefit from ECMO support versus those who may have futile outcomes 1

Oxygenation Index for Respiratory Failure

The Oxygenation Index is calculated as: (mean airway pressure × FiO₂ × 100) / PaO₂ 1

Key OI thresholds for ECMO consideration:

• OI >40: Strong indication to refer to an ECMO center in neonatal persistent pulmonary hypertension (PPHN) 1
• OI >25: Threshold where inhaled nitric oxide (iNO) acutely improves oxygenation and decreases ECMO need in newborns with PPHN 1
• OI 15-25: Earlier stage respiratory failure where iNO did not decrease ECMO incidence or improve outcomes 1

Clinical Severity Indicators Beyond Formal Scores

Pediatric Septic Shock

• Consider ECMO for fluid-refractory, catecholamine-resistant shock in children with severe sepsis 1
• ECMO should be implemented when inotropic support fails to reverse shock despite adequate fluid resuscitation 1

Pediatric Pulmonary Hypertension

• ECMO may be considered before cardiac arrest or for refractory cardiac arrest (ECPR) in children with pulmonary hypertensive crisis, low cardiac output, or right ventricular failure despite optimal medical therapy 1
• This applies as a bridge to recovery or bridge to evaluation for organ transplantation in select cases 1

Adult ARDS

• The EOLIA trial criteria for severe ARDS include patients failing conventional mechanical ventilation with lung-protective strategies and prone positioning 1
• ECMO should only be considered after optimization of conventional treatments including low-volume, low-pressure ventilation 1

INTERMACS Classification for Mechanical Circulatory Support

INTERMACS Level 1 (cardiogenic shock) patients are candidates for short-term mechanical support including ECMO, particularly when used as "bridge to decision" until hemodynamics stabilize and definitive therapy can be planned 1

Important Caveats

Timing Considerations

• The median duration of mechanical ventilation before initiating VV-ECMO is typically 2 days in severe respiratory failure 1
• At least one rescue therapy should be attempted in 81% of cases before ECMO initiation 1

Risk Stratification

• Society of Thoracic Surgeons (STS) mortality risk scores can be used preoperatively, with ECMO support potentially reducing these scores by restoring end-organ function before high-risk cardiac surgery 2
• Preoperative ECMO in patients with average STS mortality risk of 24% ± 13% significantly improved risk scores through recovery of end-organ function 2

Contraindications to Consider

• Patients should be evaluated for absolute contraindications including anoxic brain injury before ECMO initiation 2
• The presence of severe end-organ dysfunction should prompt ECMO consideration rather than delay, as ECMO can reverse acute renal failure, severe acidosis, and other organ dysfunction 2