When should Extracorporeal Membrane Oxygenation (ECMO) be considered in the emergency department for critically ill patients with severe cardiac or respiratory failure?

When to Consider ECMO in the Emergency Department

ECMO should be considered in the emergency department for patients with critical cardiopulmonary failure refractory to conventional therapy, specifically when severe respiratory failure demonstrates PaO₂/FiO₂ < 80 mmHg for ≥3 hours despite optimal ventilation, or when cardiogenic shock requires significant vasopressor support (>0.5 µg/kg/min norepinephrine) with confirmed severe left ventricular dysfunction on echocardiography. 1, 2

Clinical Indications for ECMO Initiation

Respiratory Failure (VV-ECMO)

• PaO₂/FiO₂ ratio < 80 mmHg for at least 3 hours despite optimization of mechanical ventilation, or PaO₂/FiO₂ < 100 for ≥6 hours 1, 2
• Plateau pressure > 28 cmH₂O for ≥6 hours despite lung-protective ventilation strategies 1
• pH < 7.25 for at least 3 hours due to respiratory acidosis refractory to conventional management 2
• Evidence of right ventricular overload with pulmonary artery systolic pressure > 40 mmHg and acute cor pulmonale on echocardiography 1

Cardiac Failure (VA-ECMO)

• Cardiogenic shock with very low cardiac output and reduced LV ejection fraction confirmed by echocardiography 1, 3
• Requirement for significant inotropic support and/or norepinephrine at dosages >0.5 µg/kg/min 1
• Refractory cardiac arrest with ongoing CPR when reversible etiology is suspected 4, 5
• Post-cardiotomy shock or acute coronary syndrome with cardiogenic shock unresponsive to conventional therapies 6

Critical Pre-ECMO Requirements

Optimization of Conventional Therapies Must Occur First

• Lung-protective ventilation (tidal volume 4-8 mL/kg predicted body weight, plateau pressure <30 cmH₂O) must be attempted 1, 7
• Prone positioning for 12-16 hours daily should be implemented for moderate-to-severe ARDS before ECMO consideration 7
• Other rescue therapies including neuromuscular paralysis, inhaled vasodilators, and recruitment maneuvers should be exhausted 8, 5

Timing Considerations

• VV-ECMO should be initiated within 7 days of respiratory failure onset for optimal outcomes 1
• Prolonged mechanical ventilation (>9.6 days) before ECMO is associated with significantly worse outcomes and should be avoided 1
• Early consideration is recommended before irreversible end-organ damage occurs 1

Patient Selection Algorithm

Favorable Characteristics

• Young age with fewer comorbidities and potentially reversible etiology (viral pneumonia, status asthmaticus, acute myocarditis) 8, 1
• Absence of contraindications to anticoagulation (active bleeding, recent intracranial hemorrhage, severe coagulopathy) 1
• Duration of mechanical ventilation <7-10 days prior to ECMO consideration 1

Assess Cardiac Function to Determine ECMO Type

• Perform echocardiography immediately to evaluate cardiac function and determine VV versus VA ECMO need 1
• If isolated respiratory failure with adequate cardiac function: consider VV-ECMO 1
• If combined cardiopulmonary failure or cardiogenic shock: VA-ECMO is required 1

Institutional Capability Assessment

Critical Pitfall: Do Not Attempt ECMO Without Proper Infrastructure

The American College of Chest Physicians emphasizes that ECMO should only be performed at high-volume tertiary centers with comprehensive infrastructure 3. Attempting ECMO without these resources significantly compromises patient outcomes.

Minimum Requirements for ECMO Centers

• Annual volume of at least 20-25 ECMO cases (minimum 12 cases for acute respiratory failure) 8, 1, 3
• 24/7 availability of multidisciplinary ECMO team including physicians, nurses, perfusionists, and ECMO specialists 8, 3
• Wet-primed ECMO circuit available for immediate use around the clock 8, 3
• Nurse-to-patient ratio of at least 1:1 to 1:2 for ECMO patients 8, 3

Mobile ECMO Teams for Emergency Departments Without Capability

• Each ECMO network should create mobile retrieval teams available 24/7 to retrieve patients from referring hospitals 8, 1, 3
• Mobile teams should include experienced personnel trained in critical care transport, cannula insertion, and circuit management 8
• Hospitals without ECMO capability must establish relationships with ECMO-capable institutions for timely patient transfer 1, 3, 7

Emergency Department Decision Framework

Step 1: Identify Refractory Cardiopulmonary Failure

• Document failure of conventional therapies with specific physiologic parameters (PaO₂/FiO₂, plateau pressures, vasopressor requirements) 1, 2

Step 2: Confirm Potentially Reversible Etiology

• Exclude irreversible conditions (terminal malignancy, severe irreversible neurologic injury, prolonged multi-organ failure) 1

Step 3: Assess Institutional Capability

• If your institution has an established ECMO program meeting volume requirements: activate ECMO team immediately 3
• If your institution lacks ECMO capability: contact mobile ECMO team or arrange immediate transfer to ECMO-capable center 8, 3

Step 4: Echocardiography to Guide ECMO Type

• Perform bedside echocardiography to assess cardiac function and determine VV versus VA ECMO 1

Special Considerations for Pediatric Patients

The Surviving Sepsis Campaign recommends considering ECMO for refractory pediatric septic shock and respiratory failure when conventional therapies fail 8. The same institutional requirements and volume standards apply to pediatric ECMO programs 8.

Common Pitfalls and How to Avoid Them

Pitfall 1: Delaying ECMO Consultation

• Do not wait for irreversible organ damage before consulting ECMO team 1
• Early consultation allows for optimization and preparation even if ECMO is not immediately initiated 1

Pitfall 2: Attempting ECMO at Low-Volume Centers

• Centers performing <20 cases annually have significantly worse outcomes 1, 3
• Transfer to high-volume center is preferable to local ECMO at inexperienced facility 3

Pitfall 3: Initiating ECMO Without Exhausting Conventional Therapies

• Prone positioning and lung-protective ventilation must be optimized first 1, 7
• ECMO is a rescue therapy, not a first-line intervention 8, 5

Pitfall 4: Ignoring Bleeding Risk

• Bleeding complications occur in 37% of VV-ECMO and 75.3% of VA-ECMO patients 1
• Almost all ECMO patients develop acquired von Willebrand syndrome within hours of device implantation 1
• Absolute contraindications to anticoagulation preclude ECMO use 1

Complications to Anticipate

• Intracranial hemorrhage is associated with particularly high mortality rates 3
• Thrombotic events occur in 42% of VV-ECMO patients despite anticoagulation 1
• Left ventricular overload is a specific complication of VA-ECMO requiring additional unloading devices 1
• Standardized neurological monitoring is recommended for all ECMO patients 3