What is the recommended management approach for a patient with severe respiratory or cardiac failure who is a candidate for Awake Extracorporeal Membrane Oxygenation (ECMO)?

Awake ECMO Management

Awake ECMO is a viable strategy for carefully selected patients with severe respiratory failure, allowing spontaneous breathing and early mobilization while on venovenous (VV) ECMO support, though it requires high-volume centers with multidisciplinary expertise and should only be considered when conventional therapies have failed. 1

Patient Selection for Awake ECMO

VV ECMO is indicated for isolated severe respiratory failure when cardiac function remains adequate, specifically when:

• PaO₂/FiO₂ < 80 mmHg for at least 3 hours despite optimal ventilation 1
• PaO₂/FiO₂ < 70 for ≥3 hours or < 100 for ≥6 hours despite optimization of conventional treatments 1
• Plateau pressure > 28 cmH₂O for ≥6 hours despite lung-protective ventilation strategies 1
• Evidence of right ventricular overload with pulmonary artery systolic pressure > 40 mmHg and acute cor pulmonale on echocardiography 1

Critical exclusion criteria include:

• Contraindications to anticoagulation 1
• Prolonged mechanical ventilation (>9.6 days) before ECMO consideration, which is associated with worse outcomes 1
• Cardiac dysfunction requiring hemodynamic support (these patients require VA ECMO instead) 1

Institutional Requirements

ECMO should only be performed at centers meeting strict volume and expertise thresholds:

• Minimum annual volume of 20-25 ECMO cases per year, with significantly better outcomes at higher-volume centers 1, 2
• 24/7 availability of multidisciplinary ECMO team including physicians, nurses, perfusionists, and ECMO specialists 1
• Nurse-to-patient ratio of 1:1 to 1:2 maximum 1, 2
• Quality assurance review procedures and robust expertise in ventilatory management of severe acute respiratory failure 1
• Catchment area of at least 2-3 million population to maintain adequate volume 1

Bedside Management During Awake ECMO

Respiratory Management:

• Avoid arterial hypoxemia (PaO₂ < 70 mmHg) 3
• Avoid severe arterial hyperoxia (PaO₂ > 300 mmHg), especially where reperfusion injury risk is high 3
• For patients with hypercapnia (PaCO₂ > 45 mmHg), avoid rapid change in PaCO₂ within the first 24 hours of ECMO support 3
• Serial arterial blood gas sampling in the first 24 hours of ECMO support is recommended 3

Hemodynamic Targets:

• Maintain mean arterial pressure > 70 mmHg, though individualized BP goals based on patient comorbidities are recommended 3
• Target initial ECMO flow of 3-4 L/min immediately post-cannulation, gradually increasing as tolerated 2
• Maintain arteriovenous oxygen difference between 3-5 cc O₂/100ml blood as the most reliable flow parameter 2

Temperature Management:

• Continuous monitoring of core temperature and active prevention of fever (> 37.7 °C) are recommended 3
• Hypothermia in VV ECMO is not recommended 3

Neurological Monitoring and Complication Management

Acute brain injury (ABI) occurs in 10% of VV-ECMO patients, requiring protocolized monitoring: 2

For suspected stroke:

• Obtain non-contrast head CT immediately to rule out intracranial hemorrhage 3, 2
• Do NOT administer tPA for acute ischemic stroke in ECMO patients due to prohibitively high bleeding risk 3, 2
• Proceed with mechanical thrombectomy for acute large vessel occlusion after CT angiogram confirmation 3, 2

For intracranial hemorrhage:

• Discontinue systemic anticoagulation temporarily 3
• VV ECMO may allow a longer anticoagulation-free period compared to VA ECMO 3
• External ventricular drain insertion is high-risk but may be considered in selected patients at risk of imminent death from intraventricular hemorrhage and hydrocephalus 3

Anticoagulation Balance

Anticoagulation is required for cannulation and circuit/oxygenator clot prevention but must be carefully balanced:

• Recent data shows 42% of VV-ECMO patients experience thrombotic events, 37% experience bleeding events, and 21% experience both 2
• Almost all ECMO patients develop acquired von Willebrand syndrome (AVWS) within hours of device implantation, contributing to bleeding complications 1

Mobilization and Rehabilitation

The awake ECMO strategy specifically allows for:

• Early mobilization while on ECMO support 4
• Spontaneous breathing trials to assess lung recovery 4
• Physical therapy, occupational therapy, and speech therapy as tolerated 2

Weaning Assessment

The possibility of weaning from ECMO should be fully assessed by a multidisciplinary team:

• Futility should not be determined solely by duration of ECMO 4
• Use of prolonged ECMO for lung recovery may be worthwhile 4
• Daily assessment of lung function improvement through imaging and gas exchange parameters 4

Critical Pitfalls to Avoid

Common errors that compromise outcomes:

• Delaying ECMO initiation beyond 7 days of respiratory failure onset reduces optimal outcomes 1
• Failing to optimize conventional treatments (low-volume, low-pressure, lung-protective ventilation or prone positioning) before considering ECMO 1
• Inadequate neurological monitoring leading to delayed detection of acute brain injury 2
• Over-aggressive anticoagulation without considering individual bleeding risk 2