Incidence of Bleeding, Thrombosis and Transfusion Requirements in ICU Patients With COVID-19 Supported With Veno-venous Extracorporeal Membrane Oxygenation

During the SARS-CoV-2 (COVID-19) pandemic millions of people were affected worldwide, some only experiencing minor symptoms whilst some developed acute respiratory distress syndrome (ARDS) requiring admission to the intensive care unit (ICU). ARDS is a life-threatening condition with mortality ranging from 35-48 %. Gas exchange can be severely impaired and, in some cases, conventional mechanical ventilation and adjunct therapies cannot accomplish adequate oxygenation. Veno-venous extracorporeal membrane oxygenation (V-V ECMO) is recommended as a rescue-support for refractory hypoxemia in ARDS also following COVID-19 infection and has been utilised widely. However, optimal management is difficult with prolonged ECMO duration in ARDS patients with COVID-19 and reported survival rates vary considerably 34-66

%. Complications include severe bleeding requiring more red cell transfusions and thrombotic complications, which are common despite increased risk of bleeding. Both bleeding and thrombosis are associated with increased mortality and balancing the opposing risks is challenging in daily management. On one hand, patients are routinely exposed to anticoagulant therapy (e.g. systemic heparin for the ECMO circuit operation), but on the other hand, patients are commonly exposed to blood product transfusions. The timing, monitoring, efficacy and safety of both blood product transfusion and anticoagulant therapy remains poorly understood. The investigators therefore aim to assess the risk of bleeding and thrombo-embolic complications as well as benefit and harm of blood product transfusion and anticoagulation therapy in adult ICU patients with COVID-19 supported with V-V ECMO.

Objectives

1. To assess the incidence, site and risks of bleeding and thrombo-embolic events in ICU patients with COVID-19 supported with V-V ECMO.
2. To assess the quantity of transfused blood products.
3. To assess the clinical practice of anticoagulant therapy in this cohort.
4. To assess the incidence of transfusions-related serious adverse events.

Primary outcomes

• Bleeding events [90 days]: A bleeding event is defined as any event requiring at least 3 units of red blood cells within 24 hours or transfusion with 3 or more units of either fresh frozen plasma, platelet concentrates or red blood cells within 24 hours, any intracranial bleeding or bleeding requiring invasive/surgical interventions

Secondary outcomes

• Thrombo-embolic events [90 days]: A thrombo-embolic event is defined as any radiologically proven event (i.e. ultrasound, CT- or MRI scan) or any event that led to a significant change in patient management (i.e. changes in anticoagulant therapy or requiring invasive interventions).
• Use of blood products transfusion in the ICU [90 days]: Number of units and estimated volume of red blood cells, platelets, fresh frozen plasma, fibrinogen concentrates, cryoprecipitate and anti-thrombin-III substitution
• Use of anticoagulant therapy [90 days]: Number of days on anticoagulant therapy and type of anticoagulant used in the ICU
• Transfusion-related serious adverse events [90 days]: A serious adverse event defined as any event requiring immediate discontinuation of transfusion or deterioration of any organ system that has previously been unaffected by the underlying disease following transfusion (e.g. anaphylaxis, haemolytic reactions, TRALI, TACO).30

Sex: All

Inclusion criteria:

* Adults
* Polymerase chain reaction (PCR) verified COVID-19 infection
* Supported with V-V ECMO in this center

Exclusion criteria:

\- none