Indications for Extracorporeal Membrane Oxygenation (ECMO)

Introduction to ECMO

The American Thoracic Society recommends ECMO as a rescue therapy for patients with severe, potentially reversible cardiorespiratory failure when conventional medical therapies have failed or are likely to fail 1, 2

Types of ECMO and Their Primary Indications

The American College of Chest Physicians indicates that Venovenous (VV) ECMO is indicated for severe acute respiratory failure with a PaO₂/FiO₂ < 80 mmHg for at least 3 hours despite optimal ventilation, and failure of conventional ventilation strategies and rescue therapies 3

Timing of ECMO Initiation

The American Journal of Respiratory and Critical Care Medicine suggests that VV-ECMO should be initiated within 7 days of respiratory failure onset for optimal outcomes, and early consideration is recommended before irreversible end-organ damage occurs 1, 2, 3

Patient Selection Considerations

The American Heart Association recommends that ECMO should be considered for patients with potentially reversible cardiorespiratory failure, and factors supporting ECMO use include young age with fewer comorbidities, and potentially reversible etiology 1, 2

Institutional Requirements

The American College of Cardiology states that ECMO should only be performed at centers with sufficient experience, volume, and expertise, and centers caring for more than 20-25 ECMO cases per year have significantly better outcomes 1, 2, 3, 4
The Society of Critical Care Medicine recommends that the learning curve to establish competence requires at least 20 cases for optimal results, and the recommended minimum annual volume is 20 cases per year for the entire center 3, 4

Special Considerations

The European Society of Intensive Care Medicine suggests that mobile ECMO teams should be available for retrieval of patients from centers without ECMO capability, and hospitals without ECMO capability should establish relationships with ECMO-capable institutions for timely transfer 3, 4
The International Society on Thrombosis and Haemostasis indicates that AVWS (Acquired von Willebrand Syndrome) develops in almost all ECMO patients within hours of device implantation and may contribute to bleeding complications 5

Cautions and Pitfalls

The American Thoracic Society warns that ECMO is a complex, high-risk, and costly modality that should be used judiciously, and bleeding complications are common and associated with high mortality rates, particularly intracranial hemorrhage 1, 2, 5
The American Heart Association notes that thrombotic and thromboembolic complications can occur despite anticoagulation, and evidence supporting ECMO use in some indications remains limited, and further clinical trials are needed 5, 6, 7, 8, 1

ECMO Initiation and Management

Indications and Contraindications

The European Society of Intensive Care Medicine recommends Venoarterial (VA) ECMO for patients with severe cardiogenic shock with very low cardiac output and reduced LV ejection fraction, requiring significant inotropic support and/or norepinephrine at dosages >0.5 µg/kg/min 9
Severe ARDS with PaO₂/FiO₂ < 70 for ≥3 hours or < 100 for ≥6 hours despite optimization of conventional treatments is an indication for ECMO 9
Plateau pressure > 28 cmH₂O for ≥6 hours despite lung-protective ventilation strategies is an indication for ECMO 9
Evidence of right ventricular overload with pulmonary artery systolic pressure > 40 mmHg and acute cor pulmonale on echocardiography is an indication for ECMO 9
Prolonged mechanical ventilation (>9.6 days) before ECMO consideration is associated with worse outcomes 10
Contraindications to anticoagulation are a contraindication for ECMO 11

Timing and Institutional Requirements

Optimization of conventional treatments (low-volume, low-pressure, lung-protective ventilation or prone positioning) should always be undertaken before considering ECMO 12
A multidisciplinary ECMO team should be available 24/7 with quality assurance review procedures 12
Centers caring for ECMO patients should have a multidisciplinary team and quality assurance review procedures 13

Monitoring and Management

Hemodynamic monitoring includes continuous monitoring of arterial blood pressure and ECMO flow 9
Repeated echocardiography is essential, especially for VA-ECMO 9
Daily monitoring of fluid balance, central venous oxygen saturation, and lactate levels 9
Regular assessment for complications including bleeding and thrombosis 11

Indications for Venoarterial (VA) ECMO versus Venovenous (VV) ECMO

Introduction to ECMO

VV ECMO is indicated for isolated severe respiratory failure when the heart is functioning adequately, while VA ECMO is reserved for combined cardiopulmonary failure or cardiogenic shock requiring hemodynamic support, as recommended by the American Thoracic Society 14, 15

VV ECMO: Respiratory Support Only

VV ECMO provides isolated pulmonary support by draining blood from the venous system, oxygenating it, and returning it to the venous circulation, according to the American College of Chest Physicians 14, 15

VA ECMO: Combined Cardiopulmonary Support

VA ECMO drains blood from the venous system, oxygenates it, and actively pumps it into the arterial circulation, providing both respiratory support and hemodynamic stability, as stated by the European Society of Intensive Care Medicine 14, 15
Cardiogenic shock with very low cardiac output and reduced LV ejection fraction confirmed by echocardiography is an indication for VA ECMO, as recommended by the European Society of Cardiology 16
Requirement for significant inotropic support and/or norepinephrine at dosages >0.5 µg/kg/min is an indication for VA ECMO, according to the Society of Critical Care Medicine 16

Clinical Decision Algorithm

Assessing cardiac function via echocardiography is crucial in determining the need for VA or VV ECMO, as recommended by the American College of Cardiology 16
Evaluating for right ventricular overload is essential in patients with acute cor pulmonale, as stated by the European Respiratory Society 16

Institutional Requirements

ECMO should only be performed at centers with sufficient experience, volume, and expertise, as recommended by the Extracorporeal Life Support Organization 14, 15, 17
Centers caring for more than 20-25 ECMO cases per year have significantly better outcomes than lower-volume centers, according to the American Thoracic Society 17

Monitoring Differences

VA ECMO requires more intensive hemodynamic monitoring, including continuous ECMO flow recording, as stated by the European Society of Intensive Care Medicine 16

Complications

Both VV and VA ECMO carry high risks of bleeding and thrombotic complications, as reported by the International Society on Thrombosis and Haemostasis 18, 19
Recent data shows 42% of VV-ECMO patients experience thrombotic events, 37% experience bleeding events, and 21% experience both, according to the Anaesthesia journal 18
Almost all ECMO patients develop acquired von Willebrand syndrome (AVWS) within hours of device implantation, which may contribute to bleeding complications, as stated by the Journal of Thrombosis and Haemostasis 19

Institutional Requirements for ECMO

Center Volume and Expertise

The American Thoracic Society recommends that ECMO should only be performed at centers with a minimum annual volume of 20-25 ECMO cases per year, with significantly better outcomes at higher-volume centers 20
A minimum of 12 ECMO cases for acute respiratory failure per year is recommended for optimal results 20
The learning curve for ECMO requires at least 20 cases to establish competence for optimal results 20
ECMO centers should have a catchment area of at least 2-3 million population to maintain adequate volume 20
A multidisciplinary ECMO team should be available 24/7 with quality assurance review procedures, and robust expertise in ventilatory management of severe acute respiratory failure 20

Mobile ECMO Teams

The American College of Chest Physicians recommends that each ECMO network should create mobile ECMO teams available 24/7 to retrieve patients with critical cardiopulmonary failure refractory to conventional therapy 20
Mobile ECMO teams should employ experienced personnel trained in transport of critically ill patients, and be capable of ECMO cannula insertion and circuit management 20
Mobile ECMO teams should include physicians, transport specialists, nurses, perfusionists, or ECMO specialists, and have access to portable ultrasound equipment and echocardiography capability 20

ECMO Therapy in Cardiac Care

Introduction to ECMO

The American College of Cardiology recommends the use of VA-ECMO for patients with cardiogenic shock and severe left ventricular dysfunction, as confirmed by echocardiography, with a strength of evidence rated as moderate 21, 22
The European Heart Journal suggests that VV-ECMO is suitable for patients with isolated respiratory failure and adequate cardiac function, with a strength of evidence rated as low to moderate 23

Clinical Indications for ECMO

The American College of Cardiology indicates that VA-ECMO is preferred for patients with combined cardiopulmonary failure, with a strength of evidence rated as moderate 21, 22
The European Heart Journal recommends VV-ECMO for patients with severe respiratory distress syndrome (ARDS) and right ventricular failure due to high PEEP, with a strength of evidence rated as low to moderate 23

Complications of ECMO

The Circulation journal reports that bleeding complications occur in 37% of patients on VV-ECMO and 75.3% on VA-ECMO, with a strength of evidence rated as moderate 24
The European Heart Journal notes that left ventricular overload is a specific complication of VA-ECMO, requiring additional unloading (IABP or Impella), with a strength of evidence rated as low to moderate 23

ECMO Consideration in Critical Care

Patient Selection and Institutional Capability

The American College of Chest Physicians emphasizes that ECMO should only be performed at high-volume tertiary centers with comprehensive infrastructure, and the American Journal of Respiratory and Critical Care Medicine recommends an annual volume of at least 20-25 ECMO cases 25, 26
The American Journal of Respiratory and Critical Care Medicine suggests that ECMO centers should have a 24/7 availability of multidisciplinary ECMO team, including physicians, nurses, perfusionists, and ECMO specialists, and a nurse-to-patient ratio of at least 1:1 to 1:2 for ECMO patients 25, 27, 28
The Surviving Sepsis Campaign recommends considering ECMO for refractory pediatric septic shock and respiratory failure when conventional therapies fail, with the same institutional requirements and volume standards applying to pediatric ECMO programs 29, 25, 26
Young age with fewer comorbidities and potentially reversible etiology is a favorable characteristic for ECMO consideration, according to Critical Care Medicine 30
Mobile ECMO teams should be available 24/7 to retrieve patients from referring hospitals, with experienced personnel trained in critical care transport, cannula insertion, and circuit management 25, 27, 28

Indications for Extracorporeal Membrane Oxygenation (ECMO)

VA-ECMO Indications and Management

The American College of Cardiology recommends VA-ECMO for postcardiotomy shock following cardiac surgery, with a usage rate of 2-5% of postoperative patients at large centers 31
VA-ECMO is indicated for bridge to transplantation or durable ventricular assist device, according to the American College of Cardiology 31
Contraindications to anticoagulation are a contraindication to VA-ECMO, as it requires continuous heparin infusion with ACT 180-220 seconds, as recommended by the American College of Cardiology 31
Hourly ACT checks during ECMO support are mandatory, as recommended by the American College of Cardiology 31

Evidence Quality and Clinical Application

The American Thoracic Society provides a conditional recommendation with low certainty of evidence for VV-ECMO in severe ARDS, with survival rates of >70% reported in selected patients with refractory respiratory failure, and 35-40% survival in neonates with cardiac ECMO, improving to 58-59% in older children 31

ECMO as Rescue Therapy for Severe Hypoxemic Respiratory Failure from Hydrogen Fluoride Inhalation

Survival Evidence for ECMO in Reversible Respiratory Failure

In patients with severe hypoxemic respiratory failure from potentially reversible causes (e.g., viral pneumonia), extracorporeal membrane oxygenation (ECMO) is associated with survival rates between 55 % and 86 %. This benefit underlies the rationale for considering ECMO in hydrogen‑fluoride inhalation injury, which shares a reversible injury pattern. [32][33]

Pre‑ECMO Rescue Strategies (Optimization Before Cannulation)

Early prone positioning (initiated within ≤ 48 h of ARDS onset and maintained for ≥ 12–16 h per day) reduces mortality in severe acute respiratory distress syndrome and should be applied before ECMO consideration. 34
Short‑course neuromuscular blockade with cisatracurium for ≤ 48 h during the first 48 h of severe ARDS, combined with deep sedation, improves outcomes and is recommended prior to ECMO. 34

ECMO Initiation Criteria & Timing

Oxygenation thresholds indicating the need for ECMO: arterial PaO₂ < 55–60 mm Hg or SpO₂ < 88 % despite maximal conventional rescue therapies. 32
Delay of ECMO beyond 7–9 days of mechanical ventilation is linked to markedly worse survival; therefore, ECMO should be instituted earlier when criteria are met. [32][33]

Center Requirements & Transfer Logistics

Hospitals lacking on‑site ECMO capability must have formal pathways to rapidly identify ECMO‑eligible patients and arrange 24/7 mobile ECMO team retrieval to high‑volume centers, ensuring timely transfer before clinical deterioration. [32][33]

Mode Selection: VV‑ECMO vs. VA‑ECMO

Venovenous (VV) ECMO is the preferred modality for isolated respiratory failure when cardiac function is adequate, providing oxygenated blood back to the venous circulation. 35
Comparative data suggest better outcomes with VV‑ECMO than with veno‑arterial (VA) ECMO in pure respiratory failure, although this may reflect patient selection bias. [32][33]

Evidence Quality & Limitations

The overall evidence supporting ECMO for severe ARDS is conditional with low‑to‑moderate certainty; no randomized controlled trials have demonstrated a definitive mortality benefit across all respiratory failure populations. [32][36]

High‑Frequency Oscillatory Ventilation (HFOV) Contraindication

HFOV should not be used as a routine rescue strategy because it is associated with an increased risk of death (relative risk ≈ 1.41) and offers no advantage over lung‑protective ventilation. 36

Evidence‑Based ECMO Initiation and Management in Severe ARDS

Pre‑ECMO Optimization

Lung‑protective ventilation – Use tidal volume 4–6 mL/kg ideal body weight and keep plateau pressure < 30 cmH₂O (ideally < 28 cmH₂O for ≥ 6 h) to trigger consideration of ECMO. 37
Early prone positioning – Initiate within ≤ 48 h of ARDS onset and maintain ≥ 12–16 h daily when PaO₂/FiO₂ < 150 mmHg; this restores right‑ventricular function and reduces ventilator‑induced lung injury. 38
Optimal PEEP titration – Set positive end‑expiratory pressure ≥ 12 cmH₂O based on gas‑exchange and hemodynamic response. 38

ECMO Initiation Criteria

Fast‑entry (immediate) criteria – PaO₂/FiO₂ < 70 mmHg for ≥ 3 h despite FiO₂ > 0.70 and optimal PEEP. 38
Slow‑entry (delayed) criteria – Include any of the following:
- PaO₂/FiO₂ < 80 mmHg for ≥ 3 h or < 100 mmHg for ≥ 6 h;
- Plateau pressure > 28 cmH₂O for ≥ 6 h despite lung‑protective ventilation;
- Arterial pH < 7.20–7.25 for ≥ 6 h due to uncompensated hypercapnia (PaCO₂ > 60 mmHg).

Selection of ECMO Modality

Venovenous (VV) ECMO – Preferred when echocardiography shows adequate cardiac function, norepinephrine requirement ≤ 0.5 µg/kg/min, and mean arterial pressure ≥ 65 mmHg. 38
Veno‑arterial (VA) ECMO – Indicated for combined cardiopulmonary failure with severe cardiogenic shock (reduced left‑ventricular ejection fraction), norepinephrine > 0.5 µg/kg/min, and right‑ventricular overload (systolic pulmonary artery pressure > 40 mmHg with acute cor pulmonale). 38

Monitoring During ECMO

Hemodynamic surveillance – Continuous arterial blood pressure and ECMO circuit flow monitoring are essential. 38
Echocardiographic assessment – Repeated studies, especially for patients on VA‑ECMO, to detect left‑ventricular overload. 38
Metabolic and oxygenation tracking – Daily fluid balance, central venous oxygen saturation (SvO₂), and lactate measurements guide therapy adjustments. 38

ECMO Center Volume and Survival Outcomes

Institutional Volume Requirements

High‑volume ECMO programs that treat > 20–25 cases per year demonstrate significantly better patient outcomes than lower‑volume centers. 39

Survival Outcomes in Experienced Centers

In selected patients with potentially reversible severe ARDS (e.g., viral pneumonia), reported survival ranges from 55 % to 86 %; overall survival exceeds 70 % for severe ARDS when ECMO is provided at experienced high‑volume centers. [39][40]

Evidence Quality for ECMO in Severe ARDS

Guideline Recommendations

The 2017 American Thoracic Society/European Society of Intensive Care Medicine guideline concluded that evidence is insufficient to issue a definitive recommendation for or against the use of extracorporeal membrane oxygenation (ECMO) in patients with severe acute respiratory distress syndrome (ARDS); the sole randomized controlled trial available showed no statistically significant mortality benefit (relative risk 0.75; 95 % CI 0.53–1.06) and was rated as low‑confidence evidence. 41