The Intensivists’ Dilemma: Extra-Step or No-Step for Extracorporeal Support in Patients With COVID-19
By Navitha Ramesh, MD, FCCP; Devang K. Sanghavi, MD, FCCP; and Pramod K. Guru, MD, DM
Published September 1, 2020
Dr. Ramesh is a pulmonary and critical care physician at UPMC Pinnacle in Harrisburg, PA. Dr. Sanghavi is an assistant professor of medicine in the Department of Critical Care at Mayo Clinic Florida in Jacksonville. Dr. Guru is an assistant professor of medicine in the Department of Critical Care at Mayo Clinic Florida in Jacksonville.
Intensivists practice medicine with a particular vigor and intensity. Skills, clinical judgment, and infrastructure all influence the decision to perform life-saving therapeutic modalities such as extracorporeal membrane oxygenation (ECMO). The COVID-19 pandemic adds an additional layer of complexity to this decision.
While the search for a definitive cure and vaccine continues, the ability to support the organ systems throughout the COVID-19 disease process remains the mainstay of critical care management. The majority of infected patients recover and don’t need aggressive supportive interventions. However, in a minority of patients, the illness is severe enough to require ICU admittance for respiratory or cardiorespiratory support.
Treatment of ARDS
Acute respiratory distress syndrome (ARDS) is one of the most common reasons for which ICU teams are called into action in patients with COVID-19, although the condition can still be under-recognized and underappreciated. When these patients require mechanical ventilation, the guideline-based standard of care for acute respiratory failure due to ARDS is conventional low tidal volume and fluid restrictive strategies. In some patients, however, this therapy is not sufficient.
ECMO is a more intensive method of life support that is often utilized in patients with severe ARDS. The two types of ECMO are:
- Venovenous (VV) ECMO: Poorly oxygenated blood is removed from the venous system, oxygenated, and pumped back into the venous system. This method does not provide any hemodynamic support.
- Venoarterial (VA) ECMO: This approach is used for hemodynamic and respiratory support in cardiogenic shock. Blood is removed from the venous system, oxygenated, and returned into the arterial tree.
There is controversy about the role of ECMO for care of ARDS. In the era of precision medicine, the call for evidence to support the decision remains an essential goal. ECMO is a resource-intensive and specialized care support system. Appropriate resource allocation is vital during emerging infectious pandemics.
ECMO in Patients With COVID-19
Extrapolation of experience from the 2009-2010 H1N1 pandemics remains the primary basis for the use of ECMO in COVID-19. The CESAR and EOLIA trials provide some evidence that ECMO may be helpful.
As of September 1, 2020, there were 2,392 confirmed patients with COVID-19 who had received ECMO worldwide. The majority of these patients required VV ECMO (91%), and 4% of patients received VA ECMO. The median age was 48 years, and 72% were male. The median time from intubation to ECMO initiation was 87 hours, and the median ECMO run time was 330 hours. Common complications included renal failure (25% of patients) and intracranial hemorrhage (5% of patients). The data show that 55% of patients who received ECMO for COVID-19 were discharged alive. The median length of hospital stay was 29 days, and the median duration of intubation and mechanical ventilation was 3 days.
Making the Decision to Use ECMO
There are several steps to follow when considering initiating ECMO support for patients with COVID-19.
Step 1: Determine the goals of therapy. Is ECMO being used as a support until recovery? As a bridge to transplantation? As a bridge to decision? Unfortunately, for patients with COVID-19 ARDS, there is scant evidence to help make informed decisions regarding prognosis when choosing between options.
Step 2: Identify whether the patient meets criteria for ECMO initiation. The World Health Organization recommends considering VV ECMO in specialized centers for severe ARDS. Interim guidelines from the Extracorporeal Life Support Organization suggest that VV ECMO be considered in patients with COVID-19 with severe ARDS refractory to traditional strategies and when PaO2/FIO2 ratio is <60 for 6 hours or PaO2/ FIO2 ratio is <50 for 3 hours, and/or pH is <7.2 with PCO2 >80 mm Hg for 6 hours (maintaining plateau pressure of 35 mm Hg). These guidelines are based upon the accumulated evidence from existing clinical trials and serve as a useful resource in the midst of the current pandemic. The hypothesized subcategories of COVID-19 ARDS, as well as evidence from recent trials showing a lack of benefit of early ECMO in ARDS, require that intensivists individualize the patient selection and maximize conventional ventilator support options before committing to extracorporeal support.
Step 3: Choose the ECMO modality and cannulation configurations. VV ECMO benefits patients with ARDS by correcting hypoxemia and hypercapnia, as well as allowing healing by lung rest via ultraprotective ventilation strategies. VA ECMO is a step up and is necessary for patients with cardiac decompensations. While the lungs shoulder a large burden of COVID-19 infections, incidences of myocarditis and cardiomyopathy also have been reported, possibly due to any of direct infection, cytokine storm, or secondary sepsis. The challenge is to determine the underlying pathophysiology and predict the disease course for optimal outcome.
Cannulation strategies and cannula positioning in patients with COVID-19 who require ECMO are similar to those of patients with non-COVID-19 ARDS. Cannulation for VV ECMO is typically done peripherally, either with a single catheter double-lumen cannula in the internal jugular vein or two-site cannulation of the internal jugular and femoral vein or bilateral femoral vein. VA ECMO is usually performed peripherally, and typically via the femoral artery and internal jugular or femoral vein.
However, for patients with COVID-19 ARDS, factors related to handling ECMO equipment while wearing personal protective equipment need careful planning and simulation to avoid mishaps and reduce exposure risk. The risk of exposure during cannulation must be minimized, and techniques should be used to reduce the number of staff present in the room while performing the procedure. Some institutions cannulate at the bedside to minimize travel, while others prefer to cannulate in the operating room.
Step 4: Address the need for anticoagulation. Planning is the best way to prevent complications. Smooth functioning of the ECMO circuits requires appropriate anticoagulation. Conversely, the biggest dangers of ECMO are complications related to bleeding. COVID-19 is considered a hyperinflammatory and hypercoagulable state and demonstrates a higher incidence of thromboembolic events, compared with other viral pneumonias. Choosing the ideal agent(s) for anticoagulation and determining the best way to monitor anticoagulation in patients supported by ECMO remain intense areas of research. ECMO-supported patients with COVID-19 provide a unique opportunity to examine our understanding of anticoagulation in ECMO.
Step 5: Consider the multitude of ethical issues related to both ECMO and COVID-19. The benefits of ECMO in patients with COVID-19 must be maximized, patients must be treated equally, and patients with the greatest need should be prioritized for this scarce resource, while also taking into consideration the significant patient-specific and procedure-related risks involved. The unique features of both the COVID-19 disease and the ECMO support modality should be taken into consideration. Frequent multidisciplinary interim assessments of data are suggested. The care team comprises ECMO specialists, bedside nurses, respiratory therapists, physical and occupational therapists, surgeons, perfusionists, and pharmacists.
Utilizing ECMO in patients with COVID-19 is further complicated by the lack of a comprehensive understanding of the pathophysiology of this disease, along with information overload from a multitude of sources, including social media, muddy data, personal testimonials, and poor-quality research trials. To sort through this “infodemic,” there is a need for a group of experts who can review the relevant literature and data on a regular basis and guide the care team on the ground. We suggest that this team include experts in infectious disease, rheumatology, hematology, pulmonary and critical care, hospital medicine, pharmacy, and physical therapy.
COVID-19 has magnified ethical and clinical dilemmas in the ICU. Balancing risks and benefits while managing severely ill patients in the ICU is challenging. Additionally, determining whether it is appropriate to cannulate a patient and start ECMO needs to be carefully weighed against the availability of resources, team support, and the patient’s goals of care.
For more information on COVID-19, visit CHEST's COVID-19 Resource Center.