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.