Conclusions
Here we describe our approach to a COVID-19 patient who failed medical
management and ultimately required VV ECMO. Currently there are no
specific guidelines available, therefore we have formulated an algorithm
for early identification of COVID-19 patients requiring ECMO and devised
specific management strategies to navigate their course (Figure1). This
case had several challenging aspects including hyperdynamic cardiac
function and coagulopathy.
COVID-19 has been associated with a hyperinflammatory state secondary to
cytokine storm, manifested by elevated inflammatory markers,
vasodilatory shock, and increased CO. This high output state can be
difficult to manage on ECMO due to inadequate entrainment of CO into the
circuit. Previous studies reported that extracorporeal capture of at
least 60% of the native CO is essential for a saturation of 90% or
Pa02 of 60mmHg4. Our patient responded well to the
combination of short acting beta blockers and vasoconstrictors, however
careful hemodynamic monitoring must be maintained due to concern for
cardiac dysfunction from sepsis or COVID-19 related
cardiomyopathy5. A plan to convert to a veno-arterial
configuration should be considered on a case by case basis, and invasive
hemodynamic monitoring and frequent bedside echocardiography are useful
adjuncts. Approaches to the management of persistent hypoxia while on
ECMO support are detailed in Figure1.
We anticipate that weaning of VV ECMO support in the COVID-19 cohort
will be challenging given the variable evolution of lung disease we have
observed in our non-ECMO cases manifesting with severe hypoxic failure.
Due to risks of aersolization, we deferred tracheostomy which varies
from our usual practice of early tracheostomy and reduction in sedation.
Given these changes, COVID-19 patients are at risk for deconditioning
and ventilator-associated pneumonia which may further complicate the
ability to wean ECMO.
Given reports of thrombosis in COVID-19 patients6 we
began a heparin infusion on return of abnormal laboratory values in
addition to a larger bolus of heparin before cannulation to avoid these
complications. We experienced no issues with clot formation in the
cannula or circuit but did experience persistent bleeding at the
cannulation sites prompting a trial off ECMO. While thrombosis remains a
risk, bleeding complications are significant, therefore we advise
careful monitoring of coagulation studies and ECMO circuitry in this
cohort.
To date outcomes using ECMO with COVID-19 remain poor with few details
on the specifics of patient characteristics, acceptance criteria and
management. Henry et al published the first pooled series of patients
yielding a combined ECMO mortality of 94%3,
hypothesizing the immunologic consequences of ECMO lead to worse
outcomes2. Li et al published a series of COVID-19
ECMO patients (n=8) with 50% mortality7.
In summary we were able to recover one COVID-19 patient with VV ECMO.
With careful patient selection, mechanical support is a reasonable
treatment strategy.
All authors contributed to the concept, design, drafting, revision and
approval of the article.