INTRODUCTION — The pneumonia associated with novel coronavirus disease 2019 (COVID-19 or nCoV-2) can lead to respiratory failure with profound hypoxemia requiring endotracheal intubation and mechanical ventilation. Myocardial injury associated with COVID-19 may lead to cardiogenic shock unresponsive to medical management. Patients that do not respond to optimal conventional mechanical ventilation or pharmacologic intervention may be candidates for management with extracorporeal membrane oxygenation (ECMO) in institutions with appropriate resources (equipment and personnel).
This topic will address anesthetic, surgical, and critical care considerations during initiation and management of ECMO in patients with COVID-19 associated respiratory and/or cardiogenic failure. General concepts regarding use of ECMO in other settings are discussed in other topics. (See "Extracorporeal membrane oxygenation (ECMO) in adults" and "Intraoperative problems after cardiopulmonary bypass", section on 'Extracorporeal membrane oxygenation'.)
Ventilation management and other critical care issues in COVID-19 patients who develop severe respiratory failure are also discussed in other topics. (See "COVID-19: Management of the intubated adult" and "COVID-19: Intensive care ventilation with anesthesia machines".)
PLANNING FOR ECMO USE DURING THE COVID-19 PANDEMIC
Resource considerations — Institutions without a well-established ECMO program are advised not to attempt to initiate a new program during this continuing pandemic [1-3]. ECMO is a resource-intensive therapy requiring a multidisciplinary team of experienced medical professionals with training and expertise in initiation, maintenance, and discontinuation of ECMO in critically ill patients [1-11]. Competent planning, resource allocation, and infection control are necessary to assure that ECMO is appropriately used during the COVID-19 pandemic. In institutions already near capacity due to hospitalization of COVID-19 patients, as well as those patients who have delayed care for other conditions, use of ECMO for even a limited number of cases may overwhelm the institution [1,2,4,10].
Preparations — Preparation for geographic patient surges during the current COVID-19 pandemic have focused on four components: personnel, equipment, facilities, and support systems [1,12-16].
●Personnel – Availability of a multidisciplinary team that includes clinicians in several specialties (eg, surgeons, intensivists, anesthesiologists) as well as nurses, physician assistants, nurse practitioners, respiratory therapists, and/or perfusionist technologists who have previously worked together managing ECMO patients is critically important. All team members require education regarding anesthetic, surgical, and critical care management of COVID-19 patients, including the need to use appropriate personal protective equipment (PPE) [1]. (See "COVID-19: Perioperative risk assessment and anesthetic considerations, including airway management and infection control" and "COVID-19: Management of the intubated adult" and "COVID-19: Infection prevention for persons with SARS-CoV-2 infection", section on 'Infection prevention in the health care setting'.)
●Equipment – Inventory of available durable and disposable supplies and equipment for initiation and maintenance of ECMO therapy should be determined, with plans for replacement if inventory becomes rapidly depleted during a regional pandemic surge of critically ill patients. Such planning should include routine ECMO maintenance and potential need for emergency exchange of the ECMO oxygenator due to problems with clotting, or for conversion of venovenous (VV) ECMO to venoarterial (VA) ECMO. (See 'Maintenance of anticoagulation' below and 'Conversion to venoarterial ECMO' below.)
Planning for decontamination of ECMO equipment after use is also necessary. Programs able to offer ECMO for COVID-19 patients should also be able to manage availability of this support for other indications (eg, cardiogenic shock from myocardial infarction, heart transplants, lung transplants, severe acute respiratory distress syndrome [ARDS] from non-COVID-19 disease).
●Facilities – Placement of COVID-19 patients on ECMO support in a single intensive care unit (ICU) location within a facility consolidates expertise of personnel with experience in ECMO, and reduces exposure of additional medical personnel to infection risk.
●Support systems – ECMO for COVID-19 patients is best provided in institutions with extensive relevant experience that includes:
•Assessment of appropriate and safe transfers of critically ill patients from other institutions for ECMO support
•Management of resource-intensive daily care for patients receiving ECMO (see 'Management of ECMO' below)
•Care of COVID-19 patients with severe ARDS and/or cardiac failure
INDICATIONS AND CONTRAINDICATIONS
Indications — There are two types of ECMO, venovenous (VV) and venoarterial (VA) (figure 1 and figure 2) [6]. COVID-19 patients who are potentially suited to each type are discussed in the sections below [1]. (See "Extracorporeal membrane oxygenation (ECMO) in adults".)
Indications for ECMO in patients with acute respiratory distress syndrome (ARDS) due to COVID-19 are similar to indications for its use for other causes [17,18]. We advocate that ECMO be reserved as a last resort after failure of other strategies including lung protective ventilation, prone positioning, high positive end-expiratory pressure (PEEP), recruitment maneuvers, neuromuscular blocking agents (NMBAs), and pulmonary vasodilators [1-4,10,19-21].
Data regarding use of ECMO in patients with respiratory failure due to COVID-19 are mostly observational series [1,3,5,16,20,22-24] (see "COVID-19: Management of the intubated adult", section on 'Ventilator management of acute respiratory distress syndrome'). Reports from retrospective studies have suggested variable use, ranging from 1 to 25 percent, an observation that may reflect varying availability of ECMO equipment and experienced personnel [23,25]. ECMO has been employed during other pandemics, notably the outbreaks of Middle East respiratory syndrome coronavirus (MERS-CoV) in 2012, and Influenza A (H1N1) in 2009 [26-30]. Reports from these pandemics indicated that ECMO can improve oxygenation and ventilation, as well as reduce mortality in younger infected patients with very severe lung dysfunction. Further discussion of evidence supporting use of VV ECMO in patients who need respiratory support due to various causes is available in a separate topic. (See "Extracorporeal membrane oxygenation (ECMO) in adults".)
Myocardial involvement with COVID-19 occurs in 20 to 30 percent of patients hospitalized with COVID-19 and is associated with mortality up to 50 to 60 percent [31]. Mechanisms may include inflammation, myocarditis, vasculitis, and ischemia [31]. Right ventricular failure may be the result of pulmonary embolization, hypoxemia, and direct injury. Patients that do not respond to conventional medical management may be candidates for ECMO. Further discussion of evidence supporting use of VA ECMO in patients who need cardiac support due to various causes is available in a separate topic. (See "Extracorporeal membrane oxygenation (ECMO) in adults".)
Venovenous (VV) ECMO — During VV ECMO, blood is removed from the venous system, passed through an artificial lung, and then returned back to the venous system where it passes through the lungs (figure 1). VV ECMO is an option in COVID-19 for eligible adults with ARDS refractory to conventional ventilator management, with an arterial oxygen tension/fraction of inspired oxygen tension (PaO2/FiO2) ratio <150 on a high FiO2 >90 percent and with optimized PEEP.
In some instances, a patient who requires VV ECMO and who has right ventricular dysfunction may receive a dual lumen ECMO catheter that allows function as a percutaneous right ventricular assist device (RVAD) [32], rather than initiating VA ECMO. (See 'Techniques for vascular cannulation' below and 'Venoarterial (VA) ECMO' below.)
Venoarterial (VA) ECMO — During VA ECMO, blood is removed from the venous system, passed through an artificial lung, and then returned to the arterial system (figure 2), thereby providing both cardiac and pulmonary support [33]. Use of VA ECMO in COVID-19 patients is reserved for those with severe respiratory failure accompanied by severe heart failure, RV dysfunction, excessive shunting through the lungs (eg, due to pulmonary emboli), persistent malignant arrhythmias, acute myocardial infarction, acute myocarditis, or other causes of cardiogenic shock [1,11,18]. (See "COVID-19: Evaluation and management of cardiac disease in adults" and "COVID-19: Myocardial infarction and other coronary artery disease issues".)
Contraindications — ECMO in COVID-19 patients is contraindicated in patients with severe comorbidities incompatible with recovery [1]. Examples include multiorgan failure, advanced malignancy, severe neurologic injury, cardiac arrest for a prolonged period, or central nervous system hemorrhage that is recent or expanding. (See "Extracorporeal membrane oxygenation (ECMO) in adults".)
Relative contraindications for COVID-19 patients, particularly in centers with significant resource constraints, may include [1,3,10,15,16,34]:
●Advanced age (particularly if significant frailty or other comorbidities are present; usually age >70, although age may vary based on predicted reversibility of the underlying pathophysiology)
●Morbid obesity defined as body mass index >40 kg/m2
●Severe immunocompromised status
●Advanced chronic systolic heart failure
●Extracorporeal cardiopulmonary resuscitation after cardiac arrest that does not rapidly resolve with standard advanced cardiac life support [35]
Acute kidney injury is not a contraindication to ECMO [3]. In fact, many patients with COVID-19 have acute kidney injury when ECMO is initiated, and may require ongoing renal replacement therapy during ECMO support. Ideally, ECMO can be initiated for a COVID-19 patient when duration of mechanical ventilation has been less than seven to ten days, although there is no clear cutoff [3,15].
Patients with minor or no comorbidities are prioritized when resources are limited [1,3]. When capacity of a hospital system is overwhelmed during a pandemic surge, limitations of institutional or regional resources may contraindicate use of ECMO [1]. (See 'Resource considerations' above.)
INITIATION OF ECMO
Precautions for vascular cannulation — For patients with novel COVID-19, the cannulae for ECMO are placed at the bedside in the intensive care unit (ICU) when feasible, thereby avoiding the need for patient transport to a procedural suite with fluoroscopy equipment [1]. This differs from typical management for non-COVID-19 patients. Avoiding transport of patients for catheter placement minimizes the number of health care personnel who are exposed to infection risk, and avoids disconnection from the ICU ventilator that can result in alveolar derecruitment and cardiopulmonary instability [36]. Although use of a negative pressure room is ideal for any invasive procedure performed in a COVID-19 patient, this may not be feasible if patient movement would be necessary. (See "COVID-19: Perioperative risk assessment and anesthetic considerations, including airway management and infection control".)
The airway should be secured by endotracheal intubation prior to vascular cannulation for ECMO [1]. The Centers for Disease Control and Prevention (CDC) and other organizations state that surgeons, anesthesiologists, and other clinicians participating in cannulation and initiation of ECMO should ideally wear personal protective equipment (PPE) optimal for contact, droplet, and airborne precautions (including N95 or higher respirator, or powered air-purifying respirator [PAPR]) [16]. However, if N95 respirators and PAPRs are not available or are in short supply, and the patient’s airway has been secured, then use of a surgical mask is an acceptable alternative. Further details are discussed elsewhere. (See "COVID-19: Perioperative risk assessment and anesthetic considerations, including airway management and infection control", section on 'Infection control for anesthesia'.)
Notably, insertion of ECMO cannulae may be challenging in COVID-19 patients who develop rapid deterioration [37]. Institution of emergency ECMO requires two separate teams, with one managing sudden clinical changes, while another team accomplishes vascular cannulation and establishes ECMO.
Techniques for vascular cannulation — There are three types of cannulation strategies that may be used for venovenous (VV) ECMO (listed in order of preference) for COVID-19 patients (table 1):
●The preferred approach for VV ECMO in a COVID-19 patient involves drainage from an inflow cannula that is placed in the femoral vein and threaded up into inferior vena cava until it is 1 to 2 cm below the cavoatrial junction, with return of oxygenated blood via an outflow cannula inserted into an internal jugular (IJ) vein (preferably the right IJ) and positioned near the superior cavoatrial junction (image 1) [14,16,18]. Ideally, these cannulae can provide blood flows up to 7 L/minute [38]. Flows should reach approximately 60 to 70 percent of a patient’s cardiac output to avoid hypoxemia.
The cannulae may be placed via a percutaneous or open technique. Fluoroscopy is ideal but not necessary for confirmation of cannula position. Final positioning may be accomplished with chest radiography (CXR) (image 2). While either transthoracic echocardiography or transesophageal echocardiography (TEE) may also be used to ensure optimal cannulae placement (image 3), TEE examination is avoided if possible for COVID-19 patients since this is an aerosol-generating procedure. Risk is reduced after endotracheal intubation, and appropriate protection of the echocardiographer and ultrasound equipment [39-44]. (See "Overview of perioperative uses of ultrasound", section on 'Ultrasound use during the COVID-19 pandemic'.)
●Another approach for establishing VV ECMO is insertion of a bicaval dual lumen single catheter [45]. The single catheter can be inserted percutaneously through the IJ vein, with the two drainage ports positioned in the superior and inferior vena cavae [46]. Blood is withdrawn from these drainage ports, passed through the oxygenator, and then returned via a single port that positioned near the tricuspid valve allowing flow of oxygenated blood into the right ventricle. Such catheters allow patient mobility within the ICU (eg, sitting up while intubated).
Although initial placement of a dual-port cannula is generally accomplished using fluoroscopy, placement and subsequent repositioning efforts may be accomplished using TEE alone [47-51]. However, cannula placement with TEE assistance is not ideal for a COVID-19 patient because the procedure is time-consuming and frequent readjustments may be necessary, exposing the echocardiographer to infection risk. When placement with TEE is attempted, PPE and airborne precautions appropriate for high-risk procedures are necessary [40-42]. (See "COVID-19: Perioperative risk assessment and anesthetic considerations, including airway management and infection control", section on 'PPE during airway management or aerosol generating procedures'.)
●One commercially available dual lumen atriopulmonary catheter single catheter can allow support as a percutaneous right ventricular assist device (RVAD). This device can be used with an oxygenator to provide ECMO support [16,32,52]. This particular dual lumen atriopulmonary cannula must be inserted through the right IJ vein under fluoroscopy. Blood is drained from the right atrium, passed through an oxygenator then returned to the patient just beyond the pulmonary valve in the pulmonary artery (image 4 and image 5 and image 6 and image 7 and image 8) [32]. Since fluoroscopy must be used to position this dual lumen cannula, patient transport to the fluoroscopy suite or hybrid operating room is required, which entails additional risks and the necessary infection control precautions. (See "COVID-19: Perioperative risk assessment and anesthetic considerations, including airway management and infection control".)
MANAGEMENT OF ECMO
Management of venovenous ECMO
Goals — Goals for maintaining oxygenation and ventilation during venovenous (VV) ECMO are the same for patients with respiratory failure due to novel COVID-19 as for non-COVID-19 patients.
In the absence of any significant gas exchange in the lungs, which can occur with severe acute respiratory distress syndrome (ARDS), the VV ECMO flow must be at least 60 to 70 percent of the cardiac output in order to provide adequate arterial oxyhemoglobin saturation (ie, >88 percent). This can best be accomplished by:
●Maintaining adequate ECMO flow similar to normal cardiac output (ie, 4 to 8 L/minute). If ECMO flow is limited by drainage, consider adding a second femoral drainage cannula. If the patient exhibits hyperdynamic cardiac function, an esmolol infusion may be appropriate to reduce native cardiac output. However, this strategy may not be feasible in patients with distributive shock (eg, due to sepsis).
●Ensuring that recirculation is minimized. In a well-functioning VV ECMO circuit, deoxygenated blood is drained from the patient (usually in the inferior vena cava), passed through the oxygenator for gas exchange, returned to the superior vena cava, passes to the right ventricle and through the lungs, and is then pumped systemically by the heart. If undesirable recirculation is occurring, a proportion of oxygenated blood is drained back into the ECMO circuit rather than being pumped to the right ventricle (such that blood is actually travelling directly from the return cannula to the drainage cannula). In this case, increasing ECMO pump flow will have minimal effect on systemic oxygenation [53]. If recirculation is suspected, cannulae position should be checked with a radiograph; readjustments may be necessary. The goal is to maintain at least 8 cm of separation between the cannulae ports [54].
●Maintaining oxygenation. If ECMO is not adequate for oxygenation, then efforts to ensure optimal native lung contribution typically include adjustments in mechanical ventilatory parameters, although this may induce lung injury. Other interventions such as inhaled pulmonary vasodilators or prone positioning may also be employed in selected patients. (See "Ventilator management strategies for adults with acute respiratory distress syndrome", section on 'Refractory patients'.)
Other considerations — The following additional issues are notable for COVID-19 patients [1]:
●COVID-19 patients may require more sedation than some other critically ill patients [55-57]. Higher sedation requirements in COVID-19 patients may be due to their younger age, higher respiratory drive, increased clearance caused by other medications, and a particularly intense inflammatory response [55,57]. As with other mechanically ventilated patients with ARDS, sedation should be titrated to individual patient needs. However, it may be particularly difficult to wean moderate to heavy sedation during ECMO support of a COVID-19 patient due to development of severe agitation, which can result in dislodgement of ECMO cannulae, shifts in venous return affecting ECMO flows, or ventilator dyssynchrony [55,56]. (See "COVID-19: Management of the intubated adult", section on 'Sedation and analgesia'.)
●Tracheostomy is often considered after initiation of ECMO in non-COVID-19 patients with respiratory failure to improve patient comfort and allow lightening of sedation. However, tracheostomy may be reasonably deferred in COVID-19 patients since it is an aerosol-generating procedure, and sedation requirements may be high even after tracheostomy [1,55,58].
Appropriate use of personal protective equipment (PPE) is critically important during tracheostomy in a COVID-19 patient [58,59] (see "COVID-19: Perioperative risk assessment and anesthetic considerations, including airway management and infection control", section on 'PPE during airway management or aerosol generating procedures'). Ideally, the tracheostomy is performed in the intensive care unit (ICU) rather than the operating room, thereby eliminating patient transport to another hospital location. An open rather than a percutaneous approach reduces the need for airway manipulation and bronchoscopy; however, close attention to avoidance of ventilation is necessary while the trachea is open [58,59]. Muscle relaxants are used to reduce the risk of coughing. (See "COVID-19: Management of the intubated adult", section on 'Tracheostomy'.)
●Prone ventilation of COVID-19 patients with respiratory failure is known to be advantageous during the period of mechanical ventilation before initiation of ECMO. Although prone positioning is not usually attempted during ECMO support due to risk of cannulae displacement, it may be used in selected patients, particularly if ECMO weaning is necessary due to bleeding or cannulation site infection [60]. (See "COVID-19: Management of the intubated adult", section on 'Low tidal volume ventilation in the prone position'.)
Conversion to venoarterial ECMO — Although relatively rare, conversion of VV ECMO to venoarterial (VA) ECMO may be appropriate in selected COVID-19 patients [1,16]. Development of cardiopulmonary failure with inadequate tissue perfusion or shock manifest by hypotension and low cardiac output may occur in some patients on VV ECMO support despite adequate intravascular volume, and use of standard and novel vasopressors to treat vasoplegia [61]. This may be due to right ventricular dysfunction due to severe ARDS or pulmonary emboli [62-64], or persistent malignant arrhythmias or cardiogenic shock due to acute myocardial infarction or myocarditis [33,65].
For VA ECMO, a femoral-femoral configuration is typically used (with drainage from a femoral vein and return to a femoral artery) [1]. Due to the large size of the arterial cannula that is inserted percutaneously into a femoral artery to initiate VA ECMO, lower limb ischemia complications are common [33]. Prophylactic ipsilateral placement of a distal perfusion catheter antegrade into the superficial femoral artery and continuous monitoring for limb ischemia (eg, using near-infrared spectroscopy monitoring of tissue on the calves) are strategies used to reduce complications of limb ischemia [66].
Adequacy of anticoagulation is even more critical during VA ECMO compared with VV ECMO therapy since arterial or intracardiac thromboembolic events have dire consequences [33,67]. (See 'Maintenance of anticoagulation' below.)
Maintenance of anticoagulation — Providing adequate ECMO circuit anticoagulation while avoiding bleeding or thrombosis is a challenging balancing act in these patients [68-72]. Hypercoagulability is common due to coagulation abnormalities associated with the profound inflammatory response induced in some COVID-19 patients [1,73] (see "COVID-19: Hypercoagulability", section on 'Routine testing'). Vigilant monitoring is necessary to detect development of disseminated intravascular coagulation (DIC) with thrombocytopenia, prolonged prothrombin time, and increased D-dimer, or evidence of thrombosis in the ECMO circuitry or patient sites such as the pulmonary arteries, inferior vena cava, or right atrium [1,16,63,64,73-80]. On the other hand, a high incidence of intracranial hemorrhage in anticoagulated patients receiving VV ECMO for COVID-19-related acute respiratory distress syndrome (ARDS) has also been reported [68]. Daily prothrombin time (PT), PTT, fibrinogen, and D-dimer levels are obtained to monitor for evidence of hypercoagulability, coagulopathy, and/or DIC (table 2). Some centers also monitor viscoelastic tests such as thromboelastography (TEG), or an adaptation of TEG known as rotational thromboelastometry (ROTEM) [68,69].
As in all patients supported with ECMO, adequate continuous anticoagulation is required to maintain ECMO circulation [1,71]. Monitoring anticoagulation during ECMO therapy is challenging, even in non-COVID-19 patients. Most institutions target an activated partial thromboplastin time (aPTT) that is at least 1.5 times the institutional control value, although higher targets are often used (eg, 2.0 to 2.5 times the institutional control value) [81]. A continuous intravenous heparin infusion is employed in some institutions. Many centers also use activated clotting time (ACT) to guide anticoagulation. However, ACT correlates poorly with aPTT [6,82]. Viscoelastic tests (eg, TEG, ROTEM) have also been employed to guide anticoagulation [68,69,83,84].
Some centers perform daily transthoracic echocardiography in COVID-19 patients on VV ECMO to monitor for early signs of acute cor pulmonale due to PE [5,11,62]. Formation of thrombi in the oxygenator or circuit with evidence of hypoxemia that is not due to other causes (eg, shunting through the lungs) requires oxygenator exchange. Intracardiac clot formation during ECMO is rare and mortality is high; management may involve full systemic anticoagulation or surgical embolectomy [67,79]. (See "COVID-19: Hypercoagulability", section on 'Clotting of intravascular access devices'.)
Weaning from ECMO — Improvements in lung compliance and arterial oxyhemoglobin saturation indicate that the patient may be ready for weaning from ECMO [1,6]. Typically, institutional weaning protocols are employed (algorithm 1 and algorithm 2) [1,5].
Patients with other types of ARDS may have a median duration of ECMO of 10 days, with a total length of stay in the ICU of approximately one month. However, early data for COVID-19 patients indicate that considerably longer durations of ECMO support may be necessary, with a median duration of 29 days in one study [52], with other studies reporting use of ECMO for as long as three to six weeks [3,5,20].
Continuous risk:benefit evaluation of ECMO therapy is necessary [1,3]. Although definitions of futility are institution-specific, some centers consider returning to conventional management if no lung or cardiac recovery is noted after approximately 21 days.
COMPLICATIONS AND OUTCOMES OF ECMO FOR TREATMENT OF COVID-19 — Complications of ECMO include bleeding, thrombosis, neurologic injury (from hypoxemia or thrombosis), thrombocytopenia (heparin-induced or other), and cannula-related vascular complications. Bleeding rates may be higher in patients with COVID-19 than other populations receiving ECMO. One study reported bleeding events in 29 percent [85]. In addition, bleeding events (particularly intracranial hemorrhage) were associated with mortality (adjusted odds ratio [aOR] 2.91, 95% CI 1.94–4.4). Thrombotic events occurred in 16 percent but had no impact on mortality. These and other complications of ECMO are discussed separately. (See "Extracorporeal membrane oxygenation (ECMO) in adults".)
Mortality of patients with COVID-19 on ECMO support are comparable or slightly higher than that of non-COVID-19 patients on ECMO support. Although the earliest reports from China and Europe had noted very high mortality rates >80 percent for COVID-19 patients on ECMO [9,86], subsequent studies have noted more encouraging results in the 26 to 50 percent range [3,5,14,22,52,87-94], which is comparable to that in adult patients receiving ECMO support for acute respiratory failure due to other diagnoses [88,89,95]. A 2022 meta-analysis that included 58,472 COVID-19 patients (134 studies) noted that the 4044 patients who received ECMO (6.9 percent) had an in-hospital mortality of 39 percent [93]. A subanalysis of six studies included in this meta-analysis noted that COVID-19 patients on ECMO had slightly higher mortality than influenza patients on ECMO (44 versus 38 percent; risk ratio [RR] 1.34, 95% CI 1.05-1.7).
After successful weaning from ECMO, additional time in intensive care is typically required for COVID-19 patients. Most remain on mechanical ventilation for some period of time, then additional care is typically necessary to achieve partial recovery from the severe delirium that may occur after prolonged periods of use of sedative agents and/or profound weakness after use of neuromuscular blocking agents (NMBAs) to facilitate mechanical ventilation [52,55,96].
Long-term complications occur in survivors of severe COVID-19-related acute respiratory distress syndrome (ARDS) and ECMO. Poor health-related quality of life is common due to physical limitations, psychiatric symptoms (eg, anxiety, depression, post-traumatic stress disorder), and chronic pain, similar to other patients undergoing prolonged intensive care with mechanical ventilation [97-100].
SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: COVID-19 – Index of guideline topics".)
INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5th to 6th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10th to 12th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.
Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)
●Basics topics (see "Patient education: COVID-19 overview (The Basics)" and "Patient education: Extracorporeal membrane oxygenation (ECMO) (The Basics)")
SUMMARY AND RECOMMENDATIONS
●Institutional considerations – Extracorporeal membrane oxygenation (ECMO) is a resource-intensive therapy requiring involvement of a multidisciplinary team with training and expertise in initiation, maintenance, and discontinuation of ECMO.
•Preparation – Preparations for regional surges of COVID-19 patients have focused on personnel, equipment, facilities, and support systems. (See 'Preparations' above.)
•Resources – Institutions without a well-established ECMO program should not attempt to initiate a new program during a pandemic. Even institutions experienced in ECMO therapy may reach full capacity if large numbers of hospitalized COVID-19 patients requiring mechanical ventilation. (See 'Resource considerations' above.)
●Indications – Indications for ECMO in patients with acute respiratory distress syndrome (ARDS) due to COVID-19 are similar those for other causes of ARDS. We advocate that ECMO be reserved as a last resort after other mechanical ventilatory strategies have failed including prone positioning, high positive end-expiratory pressure (PEEP), recruitment maneuvers, neuromuscular blocking agents (NMBAs), and pulmonary vasodilators. (See 'Indications' above.)
●Contraindications – Absolute contraindications for use of ECMO in COVID-19 patients include the presence of severe comorbidities incompatible with recovery (eg, multiorgan failure, advanced malignancy, severe neurologic injury, cardiac arrest for a prolonged period). Relative contraindications for COVID-19 patients may include older age, obesity with body mass index >40 kg/m2, severe immunocompromised status, or advanced chronic heart failure. Acute kidney injury is not a contraindication. (See 'Contraindications' above.)
●Types of ECMO support – There are two types of ECMO support, venovenous (VV) and venoarterial (VA) (figure 1 and figure 2). VV ECMO is typically selected for management of severe ARDS refractory to optimal ventilator management and adjuvant strategies. VA ECMO for COVID-19 patients with respiratory failure is usually reserved for those who also have right ventricular dysfunction due to severe ARDS or pulmonary emboli, persistent malignant arrhythmias, or cardiogenic shock due to acute myocardial infarction or acute myocarditis. (See 'Venovenous (VV) ECMO' above and 'Venoarterial (VA) ECMO' above and 'Conversion to venoarterial ECMO' above.)
●Initiation of ECMO support
•Precautions – Options for ECMO in COVID-19 patients are shown in the tables (table 1). Vascular cannulation and initiation of ECMO are accomplished at bedside in the intensive care unit (ICU) when feasible, thereby avoiding patient transport to a procedural suite with fluoroscopy equipment. The airway should already be secured by endotracheal intubation. Participating clinicians should wear personal protective equipment (PPE) optimal for contact, droplet, and airborne precautions. (See 'Precautions for vascular cannulation' above and "COVID-19: Perioperative risk assessment and anesthetic considerations, including airway management and infection control", section on 'Infection control for anesthesia'.)
•Vascular cannulation techniques – For COVID-19 patients, we suggest a two-catheter approach for VV ECMO involving drainage from an inflow cannula placed in the femoral vein and threaded up into the proximal inferior vena cava, with return of oxygenated blood via an outflow cannula inserted into an internal jugular vein and positioned near the superior cavoatrial junction, rather than using a dual lumen single cannula (image 1) (Grade 2C). This approach avoids the need for fluoroscopy (which involves patient transport within the hospital) or transesophageal echocardiography (which is an aerosol-generating procedure). (See 'Techniques for vascular cannulation' above.)
●Maintenance of ECMO support – Goals for maintaining oxygenation and ventilation during ECMO are the same as for non-COVID-19 patients, with the following notable issues (see 'Management of venovenous ECMO' above):
•Sedation – Weaning moderate to heavy sedation levels may be difficult due to severe agitation that may lead to dislodgement of ECMO cannulae or ventilator dyssynchrony.
•Tracheostomy – This aerosol-generating procedure may be reasonably deferred in COVID-19 patients.
•Anticoagulation strategies – Hypercoagulability is common in COVID-19 patients, with development of thrombosis in the ECMO oxygenator or other sites (eg, lung). Daily prothrombin time (PT), activated partial thromboplastin time (aPTT), fibrinogen, and D-dimer levels are obtained to monitor for evidence of hypercoagulability or disseminated intravascular coagulation (DIC) (table 2). Most institutions target an aPTT 1.5 times the upper limit of normal or higher (eg, 2.0 to 2.5 times the upper limit of normal). Vigilant monitoring is necessary to ensure adequate continuous anticoagulation and maintenance of adequate ECMO flow. Daily transthoracic echocardiography or point-of-care ultrasound is performed in some centers for early detection of acute cor pulmonale due to PE. (See 'Maintenance of anticoagulation' above and "COVID-19: Hypercoagulability", section on 'Routine testing'.)
●Weaning from ECMO support – COVID-19 patients with ARDS may require longer durations of ECMO support than other critically ill ECMO patients. Improvements in lung compliance and arterial oxyhemoglobin saturation indicate possible readiness for weaning (algorithm 1 and algorithm 2). After successful weaning from ECMO, additional time in the ICU is typically necessary to achieve partial recovery from delirium and/or profound weakness. (See 'Weaning from ECMO' above.)
