Background
SARS-CoV-2 | ECMO | |
---|---|---|
Respiratory system | Patients with COVID-19 are mainly predominant by respiratory failure. The pathophysiology of progression to ARDS in COVID-19 patients is very complicated. SARS-CoV-2 directly attacks enough alveoli epithelial cells via the ACE2 receptor to cause pulmonary edema, hyaline membrane formation and collapse of lobular of the lungs. Hypoxic pulmonary vasoconstriction failure, pulmonary embolism and/or pulmonary microcirculation embolism, abnormal immune response may also contribute to the development of ARDS | V-V ECMO mainly provides therapeutic benefits to the respiratory system by improving oxygenation and promoting lung-protective ventilation |
Cardiovascular system | It is the second cause of death after respiratory failure in COVID-19 patients. There are several possible mechanisms contributing to cardiac injury: direct injury from viral toxicity; oxygen supply-to-demand mismatch cause damage to myocardial cells; abnormal coagulation, microvascular dysfunction and plaque rupture; systemic inflammatory response and immune system disorders bringing stress to the failing myocardium and leading to further depression in myocardial function | V-A ECMO can support highly selected cases with clear evidence of refractory left ventricle dysfunction. When differential hypoxemia complicating V-A ECMO happens, hybrid V-V/V-A ECMO can be used as a remedial option. A small number of patients using ECMO could bring cardiovascular complications, including atrial thrombosis, fatal arrhythmia, etc |
Blood system | Coagulation: COVID-19 patients are characterized by a hypercoagulable state, and associated with a high incidence of thrombosis. The possible mechanism is that the direct impact of SARS-CoV-2 or related excessive inflammatory state leads to the activation of blood coagulation function Immune response: Higher-risk COVID-19 subgroups tended to have lymphopenia yet with overall leukocytosis and high inflammatory markers (CRP, fibrinogen, ferritin, IL-6). The SARS-CoV-2 attack of cytoplasmic component of the lymphocyte, spleen and lymph nodes, and the intensification in local and systemic inflammation may contribute to lymphopenia | Coagulation: ECMO can cause abnormal blood coagulation function, which can lead to thrombosis and bleeding events. Thrombosis events in COVID-19 patients receiving ECMO treatment is more common Immune response: On the one hand, ECMO technology have a certain effect of inflammatory activation. On the other hand, ECMO can reduce systemic inflammation indicators by protecting lung ventilation and completely reversing the state of systemic hypoxia It is worth noting that adequate level of anticoagulant therapy with unfractionated heparin during ECMO is a very huge challenge clinically, because of the COVID-19-related prothrombotic state and the high risk of HIT trigger |
Cerebrovascular | The incidence of ischemic stroke in patients with COVID-19 is 10.3%, and most patients have conventional stroke risk factors. Hemorrhagic stroke is relatively rare, with an incidence of 0.9%. The coagulation abnormalities of COVID-19 contributed to this result | The most common ECMO-related cerebrovascular complication is cerebral hemorrhage, with rates up to 21% |
Liver | Hepatic dysfunction was seen in 14–53% of COVID-19 patients, particularly in patients hospitalized in ICU (62%), while severe liver failure is rare. SARS-CoV-2 involvement may be related to viral direct damage to liver cells, severe infection, uncontrolled immune response | ECMO is not recommended for patients with severe liver failure |
Kidney | The prevalence of AKI among COVID-19 patients ranges from 0.5% to 5.1%, and its severity were highly correlated with poor outcomes. The potential mechanisms may include three aspects: cytokine damage, organ crosstalk and systemic effects | Improvement in kidney oxygenation due to V-V ECMO could be favorable to kidney recovery. Though, ECMO may also aggravate kidney damage by promoting cytokine generation |
Pathophysiological characteristics of critically ill patients with COVID-19
Respiratory system
Cardiovascular system
Blood coagulation and immune system
Other organs
ECMO and COVID-19
V-V ECMO and V-A ECMO in COVID-19 patients
ECMO-related complications in COVID-19 patients
Clinical outcome in COVID-19 patients receiving ECMO
Study | Spatiotemporal information | Total number of patients | ECMO Usage | Duration of ECMO use (days) | ICU overall morality, n (%) | ECMO outcome | ECMO morality, n (%) |
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Yang X [10] | 21 ICUs in Hubei, China from late December, 2019, to May 31, 2020 | 73 ICU patients | Usage rate 100% (73/73), all V-V ECMO | 18.5 (12–30) | 59 (80.8%) | 10 discharged from ICU,2 successfully weaned off ECMO but remain on mechanical ventilation, 2 remains on ECMO, 59 died | 59(80.8%) for 60-days |
Zhang G [56] | In Zhongnan Hospital of Wuhan University (Wuhan, China) from January 2, 2020 to February 10, 2020 | 44 ICU patients | Usage rate 23% (10/44), unknown mode | Unknown | 9 (21%) | 2 discharged, 5 remains on ECMO, 3 died | 3(30%) |
Zeng Y [12] | Two medical centers of Wuhan, China, early stage of COVID-19 | 12 ICU patients | Usage rate 100% (12/12), unknown mode | 11.3 (3–28) | 5 (42%) | 3 improved without ECMO, 4 still alive on ECMO but 2 with coma, other 5 died | 5(42%) |
Li X [57] | In Shanghai, China from January 30, 2020 to March 25, 2020 | 8 ICU patients | Usage rate 100% (8/8), 7 V-V ECMO, 1 V-A ECMO | 37 (18–47), expect V-A ECMO (3 h) | 4 (50%; 3 V-V ECMO, 1 V-A ECMO) | 4 died, 3 successfully weaned off ECMO but remain on mechanical ventilation, 1 still on V-V ECMO with mechanical ventilation | 4(50%) |
Belhadjer [53] | Twelve hospitals in France and one hospital in Switzerland from March 22, 2020 to April 30, 2020 | 35 child patients with febrile cardiogenic shock or left ventricular dysfunction and inflammatory state | Usage rate 28% (10/35), all V-A ECMO | 4.5 (3–6) | 0 (0%) | ECMO was successfully weaned in all | 0 (0%) |
Osho [25] | First month of the COVID-19 outbreak in Massachusetts | 6 ICU patients | 100% (6/6), all V-V ECMO | 12 (4–18) | 1 (17%) | 1 died on ECMO, 5 alive with 4 successfully decannulated, including 2 successfully extubated and 1 discharged | 1 (17%) |
Jacobs [54] | In USA from March 17, 2020 to April 9, 2020 | 32 ICU patients | Usage rate 100% (32/32), 27 on V-V ECMO, 5 on V-A ECMO | 6 (5–10) | 10 (31%) | 10 died before or shortly after decannulation, 22 alive (17 remain on ECMO, 5 successfully decannulated and extubated) | 10(31%) |
Le Breton [55] | In Paris from March 8, 2020 to April 18, 2020 | 13 ICU patients | Usage rate 100% (13/13), all V-V ECMO | 13 (3–34) | 2 (15%) | 11 alive (discharged from ICU) with 2 died on mechanical ventilation | 2 (15%) |
Kon [58] | In New York University Langone Health (NYULH) Manhattan campus from March 10, 2020 to April 24, 2020 | 27 ICU patients | Usage rate 100% (27/27), all V-V ECMO | 11 (10–14) | 1 (4%) | 26 alive (13 remain on ECMO, 13 successfully decannulated) with 1 died on ECMO | 1 (4%) |
Schmidt M [11] | In Paris–Sorbonne University Hospital from March 8, 2020 to May 2, 2020 | 492 ICU patients | Usage rate 16.9% (83/492), 81 (97%) on V-V ECMO, 1 (1%) on V-A ECMO, 1 (1%) on V-VA ECMO | 20 (10–40) | Unknown | 48 alive and discharged from the ICU, 5 alive and still in the ICU, 30 died | 30(36.1%) |
Barbaro RP [16] | At 213 hospitals in 36 countries from Jan 16, 2020 to May 1, 2020 | 1035 patients aged 16 years or older | Usage rate 100% (1035/1035), 978 (94%) on V-V ECMO, 44 (4%) on V-A ECMO, 9 (0.9%) on V-VA ECMO, and 4(0.4%) received other ECMO support | 13.9(7.8–23.3) | Unknown | 968 (94%) of 1035 patients were discharged from hospital alive (588), died (380) | 380 (39%) |
Recommendations for using ECMO in COVID-19 patients
Indications for ECMO in patients with COVID-19
Items | Explanation | |
---|---|---|
Indications | (1) Refractory ARDS despite optimal ventilation strategies (curare use, prone positioning, inhaled nitric oxide, etc.) | ① Prone positioning is strongly recommended unless clear contraindications to prone positioning, as hemodynamic instability could justify ECMO employ without previous clinical trial in prone positioning ② Inhaled nitric oxide could be considered, but it is not mandatory before using ECMO |
(2) Prolonged mechanical ventilation < 7 d | Prolonged mechanical ventilation with ventilation settings (FiO2 > 0.9, plateau pressure > 30 cmH2O) could cause irreversible lungs injury and multiple organ damage | |
(3) The use of ECMO should be considered when the risk of death is more than 50%, and should be started when the risk of death reaches or exceeds 80% | ① Mortality risk greater than 50% is measured as PaO2/FiO2 < 150 and FiO2 > 90% and/or Murray score 2–3 [62, 63]; Mortality risk greater than 80% is measured as PaO2/FiO2 < 100 and FiO2 > 90% and/or Murray score 3–4 despite optimal care for 6 h or less ② Earlier use of ECMO after respiratory failure onset (1–2 days) is more likely to benefit patients with COVID-19 | |
(4) Severe air leak syndrome | ||
(5) Complicated with severe myocarditis or cardiogenic shock | Cardiogenic shock is defined as CI < 1.8 L/min/m2 or MAP < 60 mmHg with maximum dose of vasoactive drugs (norepinephrine > 1 mcg/kg/min) or Intra-Aortic Balloon Pump | |
Con-indications | (1) Age ≥ 65 years (relative contraindications) | |
(2) Significant underlying comorbidities that cannot be recovered | Comorbidities include: CKD ≥ III, cirrhosis, dementia, advanced lung disease, uncontrolled diabetes with chronic end-organ dysfunction, severe peripheral vascular disease, severe brain dysfunction, severe damage to the central nervous system, and advanced malignant tumors | |
(3) Severe immunosuppression | Absolute neutrophil count < 0.4 × 109 /L | |
(4) Contraindications to anticoagulation | Contraindications to anticoagulation include: liver failure caused by COVID-19 combined with severe coagulopathy, major bleeding, and recent or enlarged intracranial bleeding | |
(5) Severe multiple organ failure | ||
(6) Patients who are diagnosed with acute aortic dissection | ||
(7) Inability to accept blood products |
ECMO mode selection (Table 4)
Items | Explanation | |
---|---|---|
V-V ECMO | (1) Large multi-stage, drainage cannula is recommended (e.g. 23 Fr or 11 greater for adults) | It's possible to minimize the need for insertion of an additional drainage cannula at later stage |
(2) Dual lumen cannula should be avoided if possible | Dual lumen cannula is relatively difficult to insert, is associated with higher risk of thrombotic complications and malpositioning requiring repeat echocardiography | |
(3) It's recommended that either the femoro-femoral or femoro-internal jugular configuration be used | The femoro-femoral approach allows for more rapid surgical field preparation, creates efficiency of movement around the bed, and keeps the operator away from the patient's airway | |
V-A and V-VA ECMO | (1) A femoro-femoral configuration for V-A ECMO cannulation is recommended | |
(2) A distal limb perfusion catheter is strongly recommended to reduce the risk of limb ischemia | ||
(3) It's recommended to place three separate single lumen cannulas for the utilization of V-VA ECMO and not recommended to use a double lumen cannula for V-VA ECMO | ||
(4) The initiation of V-VA ECMO as a pre-emptive strategy is not recommended | If a patient requires V-V ECMO but has no evidence of cardiac dysfunction or cardiac dysfunction is medically supportable with inotropes, placement of an arterial cannula is strongly discouraged |