ECMO
Treatment options for COVID-19 myocarditis are still evolving. However,
mechanical circulatory support devices and life support therapies such
as veno-venous ECMO (VV-ECMO) and VA-ECMO may be beneficial in select
cases.
The mortality in COVID-19 patients who require mechanical ventilation is
high. Extracorporeal membrane oxygenation can be lifesaving in patients
with severe forms of ARDS, or refractory cardio-circulatory compromise.
While accepting that resource scarcity may be the overwhelming concern
for healthcare systems during this pandemic, VA-ECMO can be considered
in highly selected cases of refractory CS and biventricular failure. The
decision to initiate this therapy should take into consideration the
availability of resources, perceived benefit, and risks of transmitting
disease to patients and staff.
The Extracorporeal Life Support Organization (ELSO) recommends
consideration of VA-ECMO in refractory CS that persists despite adequate
fluid resuscitation, inotropes, and vasopressor support.[24]
Contraindications to VA-ECMO include advanced age, life- threatening
noncompliance, and significant medical comorbidities.[24]
The Society of Critical Care Medicine guidelines for the management of
COVID-19 patients recommends the use of ECMO when conventional
management fails.[25] Due to the intensive hospital resource
utilization, substantial staff training, and multidisciplinary needs
associated with starting an ECMO program, ELSO recommends against
starting new ECMO centres for the sole purpose of treating patients with
COVID-19. During the COVID-19 surge, it is reasonable to concentrate
those patients with the greatest chance of benefit from receiving ECMO
in a hospital where an experienced ECMO team is available.
Patient selection for VA-ECMO in the setting of COVID-19 infection is a
challenging task. However, a multidisciplinary CS team that includes
representation of cardiac surgery, cardiology, intensive care,
anaesthesia, and advanced heart failure/transplant physicians may
facilitate decision-making.
Although patients with COVID-19 infection are in a proinflammatory and
prothrombotic state, coagulopathy occurs in up to one-fifth of
cases.[26] Thus, vigilant monitoring for both thrombotic
complications (intracardiac thrombi, aortic root/aortic valve thrombi,
cannula thrombi, thrombosis of oxygenator) is necessary. Severe cases of
COVID-19 tend to present with multi-organ failure. The use of VA-ECMO in
such patients may be considered a futile resource-intensive endeavour.
Use of validated prognostic scores such as the Sequential Organ Failure
Assessment and Survival after Veno-arterial ECMO scores together with
clinical judgment may identify those who are more likely to
recover.[27]
The provision of ECMO, also is dependent on local institution and
regional policies. ECMO requires specialized equipment, training (of
physicians, nursing staff, and perfusionists), and delivery of care in
specialized critical care units. MacLaren et al.[28] suggest,
resources may well be better concentrated to ensure that enough ICU
beds, ventilators, and personal protective equipment are available to
deal with the influx of patients encountered during the pandemic.
Providing this level of care should be considered dynamically on a
case-by-case basis as the local situation and resource availability
changes (ie, critical care beds, healthcare personnel, equipment).
Many factors could affect the outcomes of ECMO treatment, including the
duration of mechanical ventilation, the severity of underlying disease,
the experience of trained medical staff, and ECMO equipment. Use of ECMO
in patients with a combination of advanced age, multiple co-morbidities,
or multiple organ failure should be avoided.
Not all patients will improve with ECMO support. As is standard with
usual ECMO care, clinicians should be continuously evaluating when ECMO
no longer provides a positive benefit:risk ratio and should at that
point return to conventional management. As prognosis is worse with time
on invasive mechanical ventilation, patients on mechanical ventilation
greater than 7 days can probably be excluded and observing no lung or
cardiac recovery after approximately 21 days on ECMO can be considered
futile.
In the present time of global uncertainty with limited evidence to guide
care, we must be mindful of balancing resource scarcity. We anticipate
that Extracorporeal Membrane Oxygenation for 2019 Novel Coronavirus
Acute Respiratory Disease (ECMO-CARD), an ongoing multicentre
prospective observational study of ECMO use in COVID-19, will inform
practice for both VV-ECMO and VA-ECMO use when published.[29] For
now, it seems reasonable to reserve VA-ECMO for highly selected cases of
COVID-19 where there is a perceived reasonable probability of recovery.