Viscoelastic haemostatic assays in aeromedical transport

To assess the feasibility of using rotational thromboelastometry (ROTEM®)-sigma and thromboelastography (TEG®)-6s viscoelastic point-of-care assays during rotary wing aeromedical transport, and to determine the reliability of the results obtained.

A single centre, prospective, observational, non-interventional feasibility study performed at Gold Coast University Hospital intensive care unit, and in a LifeFlight Retrieval Medicine operated Leonardo AW139 helicopter. Blood was collected from eight healthy volunteers on 18 April 2019 and all testing was performed on that day. Functions measured were ROTEM-sigma extrinsically activated thromboelastometry (EXTEM) clotting time (CT), EXTEM amplitude at 5 min after CT (A5) and fibrin-based extrinsically activated thromboelastometry (FIBTEM) A5, and TEG-6s Kaolin (CK) reaction time (R), functional fibrinogen (CFF) maximal amplitude (MA) and CFF amplitude at 10 min after R (A10). Differences between the results obtained in the helicopter and control results at Gold Coast University Hospital during flight and after flight, and also differences in control results over time up to 3 h were analysed.

During flight both the ROTEM-sigma and TEG-6s devices failed to give reliable results. Post flight, the helicopter and control samples correlated well. Repeat testing of control samples at 1 and 3 h also revealed good correlation over time.

It is feasible to reliably run tests on both the ROTEM-sigma and TEG-6s after the devices have been flown in a rotary wing aircraft. However, testing cannot be performed while in flight conditions. It is also possible to run blood samples collected up to 3 h prior and acquire results which correlate well with initial testing.