Extracorporeal Membrane Oxygenation Support in 2019 Novel Coronavirus Disease: Indications, Timing, and Implementation
The 2019 novel coronavirus disease (COVID-19) emerged as a global health crisis, rapidly spreading across Hubei province and eventually to all regions of China due to its person-to-person transmission and strong invasiveness targeting the lower respiratory tract. By February 15, 2020, over 68,000 cases of COVID-19 pneumonia had been confirmed in China, including more than 1,600 fatalities. While most infected patients experienced mild symptoms and recovered completely, a subset of patients rapidly progressed to acute respiratory distress syndrome (ARDS) and multi-organ failure. Early clinical data from Wuhan Jinyintan Hospital revealed that ARDS was reported in 29% of 41 confirmed patients, with 13 requiring intensive care unit (ICU) admission, 4 receiving invasive mechanical ventilation, and 2 treated with extracorporeal membrane oxygenation (ECMO). Among these 41 patients, 6 ultimately died. Another study from the same hospital involving 99 confirmed patients showed that 17 developed ARDS, 3 received ECMO, and 11 died. Similarly, a separate study reported that 16% of 138 cases progressed to ARDS, with 4 requiring ECMO support.
The rationale for using ECMO in severe respiratory and/or cardiac failure has been well-established, particularly in the context of viral pneumonia. During the 2009 H1N1 influenza pandemic, ECMO proved to be a valuable intervention. Similarly, the Middle East respiratory syndrome coronavirus (MERS-CoV) epidemic in 2012, which had a fatality rate of 34.4%, highlighted the potential benefits of ECMO in treating refractory hypoxemia and multi-organ failure. A study by Alshahrani et al. reported that among 35 critically ill MERS-CoV patients with refractory hypoxemia, 17 received veno-venous ECMO (VV-ECMO), resulting in a significantly lower fatality rate compared to those who received only conventional respiratory care (65% vs. 100%). Given the similarities between MERS and COVID-19, the therapeutic potential of ECMO in COVID-19 is worth considering, despite the limited evidence available at the time of writing.
Indications for ECMO in COVID-19 patients should be guided by the principles established for severe viral pneumonia and ARDS management. ECMO should be considered when standard conventional respiratory care fails to correct respiratory failure. This includes lung-protective mechanical ventilation strategies, such as maintaining a tidal volume of ≤6 mL/kg, plateau pressure <30 cmH2O, and positive end-expiratory pressure ≥10 cmH2O, as well as the use of lung recruitment maneuvers, prone positioning, neuromuscular blockade, and sedation. Specific indications for ECMO include: (1) PaO2/FiO2 600 mmHg; (2) ventilator frequency >35 breaths per minute, pH 30 cmH2O; (3) age <65 years; and (4) mechanical ventilation duration <7 days. Alternatively, based on the ECMO to Rescue Lung Injury in Severe ARDS trial, ECMO should be considered if patients meet one of the following criteria: (1) PaO2/FiO2 <50 mmHg for more than 3 hours; (2) PaO2/FiO2 <80 mmHg for more than 6 hours; or (3) arterial blood pH 60 mmHg for more than 6 hours. Early implementation of ECMO, particularly when PaO2/FiO2 is between 100 and 150 mmHg, has been shown to minimize respiratory-driven pressure, inhibit pulmonary and systemic inflammation, and reduce severe dysfunction of the lungs and extrapulmonary organs. Early “awake ECMO” treatment may also be considered in younger patients without extrapulmonary organ disorder or serious co-infection, as they are more likely to benefit from this intervention.
The implementation of ECMO in COVID-19 patients requires careful consideration of the risks associated with the infectivity of the 2019 novel coronavirus (2019-nCoV). ECMO procedures can generate various body fluid splashes, including airway secretions and blood, posing a high risk of nosocomial infections. To minimize these risks, standardized protocols and protective measures must be followed. Recommendations for performing ECMO in COVID-19 patients include: (1) placing patients in an independent area in the ICU under negative pressure or ensuring adequate ventilation if negative pressure is unavailable; (2) restricting the number of staff in the independent area and carefully inspecting all supplies, including surgical instruments, consumables, medications, and blood products; (3) providing all staff with biosafety level 3 protection and, if necessary, comprehensive airway protective devices such as positive pressure medical protective hoods; (4) using a bedside ultrasound device to evaluate vascular conditions, monitor cardiopulmonary interaction, and assess hemodynamic status; (5) performing catheterization under ultrasound guidance with the bed unit elevated to an optimal position; (6) considering dual-lumen catheter for the jugular vein as the best choice due to its advantages in operation and later rehabilitation; and (7) prioritizing VV-ECMO as the primary mode, while considering veno-arterial ECMO for patients with myocarditis, a common complication associated with H1N1 influenza A and MERS-CoV infections.
ECMO is a highly skilled and high-risk operation that is frequently demanded in the rescue of COVID-19 patients. Establishing more ECMO centers in affected cities, particularly in Hubei province, is crucial. Expert ECMO teams should be organized for immediate and professional rescue. A standard ICU single room is recommended, and daily care by ICU-specialized nursing teams should be established to avoid lethal complications. All ECMO-related equipment and consumables should be distributed or deployed by a centralized department.
Key knowledge gaps about ECMO in the context of COVID-19 include the need for more actionable data linking to the novel disease. More information is needed on the pathophysiology and effective treatment of COVID-19 patients. Each ECMO team will face new serious challenges in this battle. Information collected from the practice of ECMO for severe COVID-19 must be compiled and shared. The creation of recommendable ECMO procedures and the rescue of severely and critically ill COVID-19 patients are essential steps in addressing this global health crisis.
doi.org/10.1097/CM9.0000000000000778
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