Coagulation and platelet function in cold-stored whole blood on missions in a helicopter emergency service

Haemorrhage is a leading cause of morbidity and mortality in trauma, and prehospital transfusion of blood products is often necessary. Whole blood has been proposed to be the best alternative, but it is unclear whether, and how, storage and transport of the blood in a helicopter affects the blood units. We investigated the coagulation capacity and platelet function in whole blood at different time points during helicopter missions.

Twenty units of low-titre group O RhD negative whole blood were collected from healthy volunteers and analysed before, during and after transport in a helicopter. Coagulation and platelet function, as measured by thromboelastography, and blood samples for pH, electrolytes, glucose and lactate were assessed at baseline and 24, 72 and 168 h after storage in the helicopter. Plasma concentrations of coagulation factors and haemoglobin and blood counts were measured at baseline and after 168 h.

Plasma concentrations of coagulation factors and haemoglobin did not change during storage and transport. Platelet counts decreased from a baseline mean of 172 ± 29 × 10⁹/L to a mean of 120 ± 28 × 10⁹/L after 168 h, and platelet function worsened slightly but significantly by 8%-9% during storage and transport. pH and glucose decreased while potassium and lactate levels increased after 168 h compared with baseline.

Storage and transport of whole-blood units in a rescue helicopter, for up to 168 h, had a slight impact on the blood quality. Storage of whole blood on board of the helicopter holds up to European standard, measured as temperature and haemolysis.