(P-TS-98) Simulating Direct Transfusion Using Syringe-Based Collection of Whole Blood from Universal Donors

Background/Case Studies: Direct transfusions using the walking blood bank are an option for urgent battlefield resuscitation to combat casualties and may be the only viable option in a cold weather operating environment where blood may freeze when stored by traditional means. A direct transfusion involves administration of blood from one individual to another without the use of an intermediate storage container. Due to concerns over blood compatibility and clotting in the transfusion set, direct transfusions pose risks to the recipient. This study aimed to determine the safety and feasibility of a direct transfusion by collecting whole blood from a donor and immediately “transfusing” the blood to a waste container.

Study

Design/Methods: This pilot study included six volunteer donors who were prepped for whole blood unit collection. Blood was collected using an 18-gauge needle through a 79 mm extension tubing set connected to a three-way stopcock and 60 mL syringe. Blood was drawn in 60 mL intervals and pushed to a waste container through a second 79 mm extension tubing set. Study endpoint was the collection of 400 mL or the inability to continue the draw due to clotting or resistance. Samples were collected at baseline, 240 mL, and endpoint. Blood was drawn at the fastest rate possible that would not cause discomfort to the patient. Visible clotting was monitored, and thromboelastography, complete blood count, coagulation, and chemistry testing were performed on the blood samples.

Results/Findings: The total draw time for each subject ranged from 9:33 to 15:10. Visible clotting was observed in all draws that took over 11 minutes to complete. In the blood samples, clot strength and fibrinogen decreased in the 240 mL and endpoint samples from the two donations with the longest draw times (13:07 and 15:10). In 5 of the 6 cases, the platelets decreased in the 240 mL and endpoint samples (Figure A). A one-way ANOVA showed that platelet counts between the three timepoints were not statistically significant, F(2, 12) = 0.41, P = 0.671.

Conclusions: Visible clotting and decreased clot strength and fibrinogen associated with longer draw times suggest that draw rate is a critical component for direct transfusion safety. Instead of basing direct transfusion collection on volume, these data support limiting the collection time to prevent clots from being transfused into the recipient. Additionally, the decrease in platelets may be caused by contact activation with the medical tubing, which could be ameliorated by using a shorter tubing set for the procedure.