Effect of Fresh Whole Blood Donation on Human Performance in United States Special Forces

Fresh whole blood has been the standard of care for the treatment of hypovolemia secondary to blood loss in the Tactical Combat Casualty Care guidelines since 2014. Current recommendations from the Prolonged Field Care Working Group state that the impact on mission performance is not degraded with 1 unit (450mL) of donation. Because there is limited information on combat performance after donation, the purpose of this investigation was to examine the effects of blood donation on simulated battlefield tasks in U.S. Special Forces Soldiers.

A total of 17 U.S. Special Forces Soldiers participated in this study. Soldiers served as their own controls and were subject to blinded blood draw and a sham draw, which were ordered randomly and separated by 6 days. Outcome measures consisted of performance, capillary blood lactate, salivary osmolality, heart rate, and estimated core temperature. These measures were taken at baseline, then immediately following a 1,200-m shuttle run, 3-event stress shoot, and 5-mile run, all while wearing a typical combat load.

There was a moderate-to-large, statistically significant (p<0.05) increase in shuttle run time due to blood donation (δ=12.5s, Hedges' g=1.0). We also detected moderate, statistically significant increases in shooting scores (δ=29.2s, Hedges' g=0.5) and 8-km run times (δ=3.9m, Hedges' g=0.7) due to blood donation. There was no interaction between event and blood draw condition for heart rate, estimated core temperature, blood lactate, or salivary osmolality. Blinding was only 26% effective, as Soldiers were able to correctly identify the procedure that they were subjected to 74% of the time.

The moderate-to-large performance decrements found in this study are somewhat greater than those of previous studies. We believe that our results may be different due to the more demanding tasks that were performed after the blood draw in our investigation.