What are the guidelines for the initial setup and management of Veno-Arterial (VA) Extracorporeal Membrane Oxygenation (ECMO)?

VA ECMO Initial Setup and Management

Facility and Equipment Requirements

A wet-primed ECMO circuit must be available 24/7 for immediate deployment, with circuit changes completed in under 15 minutes during malfunction. 1

• An Uninterrupted Power System (UPS) supporting all equipment for a minimum of 45 minutes is mandatory to prevent catastrophic power failures 1
• Backup components for all circuit elements must be immediately accessible at the bedside 1
• Doppler echocardiography machines with physicians trained in vascular and cardiac echocardiography are required for cannulation guidance and ongoing surveillance 1

Staffing Requirements

Maintain a nurse-to-patient ratio of 1:1 to 1:2 maximum (one nurse for up to two ECMO patients maximum). 1

• An ECMO program director (physician) must oversee overall operations, training, equipment maintenance, and quality improvement 1
• The multidisciplinary team should include intensivists, perfusionists, neurologists, surgeons, and specialized nursing staff 2

Initial Hemodynamic Management

Target initial ECMO flow of 3-4 L/min immediately post-cannulation, gradually increasing as tolerated. 1, 3

• Maintain arteriovenous oxygen difference between 3-5 cc O₂/100ml blood as the most reliable flow parameter 1, 3
• Target mean arterial pressure >70 mmHg to ensure adequate cerebral and end-organ perfusion while minimizing left ventricular afterload 1, 3
• Monitor for left ventricular distension, which occurs when the heart cannot eject against the increased afterload from retrograde ECMO flow 4, 5

Oxygenation and Ventilation Targets

Maintain PaO₂ >70 mmHg to prevent hypoxemia-associated acute brain injury, while avoiding severe arterial hyperoxia (PaO₂ >300 mmHg). 3

• Optimize mechanical ventilation with lung-protective strategies even while on ECMO support 4
• Monitor for differential hypoxemia in peripheral VA ECMO, where poorly-oxygenated blood from the failing native heart may perfuse the upper body (brain and coronary arteries) while well-oxygenated ECMO blood perfuses the lower body 6, 4

Monitoring for Differential Hypoxemia (Mixing Point)

Obtain arterial blood gases from a right radial arterial line to best represent cerebral oxygenation, as this site approximates what the brain receives. 6

• A wide pulse pressure on right radial arterial line monitoring indicates significant left ventricular ejection reaching the upper body, suggesting a distal mixing point 6
• When differential hypoxemia is detected (upper body hypoxemia despite adequate lower body oxygenation), immediately increase ECMO flow to move the mixing point proximally toward the innominate artery 6
• Consider V-AV ECMO configuration by inserting an additional oxygenated return cannula in the jugular vein if increasing flow and optimizing ventilation fail to correct upper body hypoxemia 6

Neurological Monitoring Protocol

Implement protocolized neurological monitoring immediately, as VA ECMO carries a 19% acute brain injury risk (versus 10% in VV ECMO). 2, 1, 3

• Perform continuous cerebral oximetry to detect acute brain injury early, especially for peripheral VA ECMO patients at risk for differential hypoxia 2, 1
• Conduct intermittent EEG and somatosensory evoked potentials (SSEP), particularly in comatose patients; continuous EEG is preferred to detect non-convulsive seizures 2
• Perform pupil assessment at regular intervals; use pupillometry if available 2
• Obtain early neuroimaging (non-contrast head CT) for ECMO patients at risk of acute brain injury based on physical examination and neuromonitoring tools 2

Blood Pressure Management for Neuroprotection

Individualize blood pressure targets based on the type of acute brain injury present. 2

• For acute ischemic stroke: Allow permissive hypertension (BP ≤ 220/120 mmHg) to maintain adequate cerebral perfusion if the heart can tolerate the increased afterload 2
• For intracerebral hemorrhage: Target lower blood pressure (systolic BP < 140 mmHg and MAP < 90 mmHg) due to anticoagulation-associated bleeding risk 2
• Recognize that low pulse pressure (< 20 mmHg) in the first 24 hours of VA ECMO is associated with acute brain injury 2

Anticoagulation Management

Anticoagulation is required for cannulation and to prevent clot formation in the circuit and oxygenator, but must be balanced against high bleeding risk. 2

• Recent analysis shows 42% of VV-ECMO patients experience thrombotic events (mostly circuit thrombosis), 37% experience bleeding events, and 21% experience both complications 2
• The optimal anticoagulation strategy remains empirical with limited high-quality evidence; practice is highly variable 2
• Key knowledge gaps include the safe duration of holding anticoagulation for patients with intracranial hemorrhage supported by VA ECMO 2

Quality Assurance and Data Management

Submit data to the ELSO registry or equivalent database for cross-institutional analysis. 1

• Hold formal multidisciplinary meetings routinely to analyze activity and review equipment needs 1
• Maintain structured protocols to promote excellence in team care and consistent management 4

Common Pitfalls to Avoid

• Failure to recognize differential hypoxemia: Always monitor right radial arterial blood gases and pulse pressure in peripheral VA ECMO 6, 4
• Inadequate neurological monitoring: Given the 19% acute brain injury risk in VA ECMO, protocolized neuromonitoring is not optional 2, 1
• Left ventricular distension: Monitor for this complication, which can lead to pulmonary edema, thrombus formation, and myocardial ischemia 4, 5
• Delayed intervention for complications: Circuit changes must occur in under 15 minutes; delays can be catastrophic 1