The HITEC Study
Haemostasis and Immunothrombosis in Extracorporeal Circuits (The HITEC Study)
Imperial College London
Duration of Study in the UK
4 years, 0 months, 1 days
Patients with severe cute respiratory failure (SARF) who have failed conventional mechanical ventilation and acute respiratory distress syndrome (ARDS) therapies may require Extracorporeal membrane oxygenation (ECMO), a form of mechanical support for the heart and lungs. Use of ECMO is increasing with surges during the 2009 flu and 2020 coronavirus pandemic. Whilst on ECMO, blood within the circuit is exposed to a large surface area of foreign material (tubing, plastic etc) which can activate the clotting cascade leading to thrombosis. To reduce to risk of developing thromboses in the circuit, patients on ECMO are started on anticoagulation.
Despite adequate anticoagulation some patients still develop thromboses particularly at the membrane oxygenator (MO). In some cases, development of thromboses requires the circuit to be changed, a potentially high-risk event in patients who are completely dependent on ECMO. However, predicting the need for circuit change is often difficult and relies on a combination of blood results and ECMO mechanical data.
The reason why some patients clot more than others is not fully understood. Patients require ECMO usually due to severe infection and inflammation. Activation of the immune system particularly neutrophils, can lead to release of intracellular proteins in extracellular vesicles (EV) and web-like structures called neutrophil extracellular traps (NETS). These intracellular components can activate the clotting cascade, a process called immunothrombosis.
This study aims to quantify and compare levels of immunothrombosis between patients on ECMO who require circuit changes to those who do not. We will extract data from clinical systems and take longitudinal blood samples to examine trends in existing clinical markers, quantify markers of immunothrombosis (NETs and EV) and correlate with clinical thrombosis. We will also re-circulate blood in discarded ECMO circuits after a circuit change and after discontinuation of ECMO support to analyse the effect of the ECMO circuit on immunothrombosis.
Wales REC 3
Date of REC Opinion
12 Jan 2022
Further Information Favourable Opinion