Assessing direct transfusion feasibility with syringe-based collection of whole blood from universal donors

The anticipated multidomain operations of future battlefields necessitates minimalistic medical strategies for treatment of combat wounded. Direct transfusion, involving the administration of blood directly from a donor to a recipient, may be a solution for treating hemorrhagic shock patients in an austere environment where the tools to execute clinical practice guidelines are unavailable.

Six participants were enrolled in this observational pilot study. Blood was drawn through medical tubing using a 60 mL syringe and pushed through a second medical tubing set with output to a waste container. Three participants were collected with untreated lines, and three collections were performed with heparin flushed lines. Visible clotting was assessed, and blood samples were collected from the output at baseline, after 240 mL of blood collected, and at study endpoint, which was 400 mL collection or termination due excessive clotting or draw difficulties. Coagulation, hematology, and chemistry testing were performed on the samples.

Visible clotting was observed at endpoint in the four procedures with the longest draw times. There were statistically significant differences in platelet count and fibrinogen concentration between baseline and endpoint samples of the non-heparin group. Clot strength decreased over time in the non-heparin group.

The association between longer procedure times and visible clotting indicates direct transfusions should be completed based on time constraints rather than target volumes. Maintenance of platelet count, fibrinogen concentration, and clot strength in the heparin group suggest that heparin coated lines may enhance the safety of direct transfusions.