Page 25 - JSOM Spring 2025

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

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Alex P. Houser, DO ; Mario A. Soto, MD ; Kathryn S. Bell, MS ;
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Paul G. Goldberg, MS, RD ; Kevin J. Cronin, MS ;
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Rick C. Caldwell, 18D, SO-ATP ; Brian K. Schilling, PhD *

ABSTRACT
Background: Fresh whole blood has been the standard of care authorized to conduct blood transfusions in the absence of
for the treatment of hypovolemia secondary to blood loss in a provider. United States Special Forces Medical Sergeants
the Tactical Combat Casualty Care guidelines since 2014. Cur- (18D) and other graduates of the Special Operations Combat
rent recommendations from the Prolonged Field Care Working Medic (SOCM) course are authorized to perform blood trans-
Group state that the impact on mission performance is not fusions without a provider present and can easily be found in
degraded with 1 unit (450mL) of donation. Because there is situations with delayed evacuation that require the battlefield
limited information on combat performance after donation, administration of FWB. Regardless of who is authorized to
the purpose of this investigation was to examine the effects of perform blood transfusions, circumstances may require blood
blood donation on simulated battlefield tasks in U.S. Special donors to remain in the combat environment, and how dona-
Forces Soldiers. Methods: A total of 17 U.S. Special Forces tion may affect their tactical performance is not well described.
Soldiers participated in this study. Soldiers served as their The practice of battlefield blood transfusion has been effec-
own controls and were subject to blinded blood draw and a tively employed in modern combat since World War I as a
sham draw, which were ordered randomly and separated by 6 life-saving modality. As technology has advanced, there has
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days. Outcome measures consisted of performance, capillary been a shift away from FWB transfusion with a focus on
blood lactate, salivary osmolality, heart rate, and estimated component therapy. Component therapy consists of a 1:1:1
core temperature. These measures were taken at baseline, then ratio of red blood cells (RBC), fresh frozen plasma (FFP),
immediately following a 1,200-m shuttle run, 3-event stress and apheresis platelets. However, the ability to store the
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shoot, and 5-mile run, all while wearing a typical combat load. required components is constrained due to cold-chain man-
Results: There was a moderate-to-large, statistically significant agement requirements, therefore limiting access to elements
(p<0.05) increase in shuttle run time due to blood donation operating in far forward environments. With this limited
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(∆=12.5s, Hedges’ g=1.0). We also detected moderate, statisti- access, the need for immediate and life-saving damage con-
cally significant increases in shooting scores (∆=29.2s, Hedges’ trol resuscitation measures like FWB transfusions may help
g=0.5) and 8-km run times (∆=3.9m, Hedges’ g=0.7) due to achieve hemodynamic stability prior to medical evacuation
blood donation. There was no interaction between event and (MEDEVAC).
blood draw condition for heart rate, estimated core tempera-
ture, blood lactate, or salivary osmolality. Blinding was only The need for each Servicemember to perform optimally is cru-
26% effective, as Soldiers were able to correctly identify the cial, given that combat scenarios require maximal and sub-
procedure that they were subjected to 74% of the time. Con- maximal exercise conditions. In situations where a walking
clusion: The moderate-to-large performance decrements found blood bank is initiated, these Servicemembers are potential
in this study are somewhat greater than those of previous stud- blood donors, which is likely to affect their physical perfor-
ies. We believe that our results may be different due to the mance on subsequent missions as their bodies recover. The
more demanding tasks that were performed after the blood need for each Servicemember to perform optimally is crucial,
draw in our investigation. since combat scenarios vary between maximal and submaxi-
mal exercise conditions. Current literature focusing on physio-
Keywords: combat medicine; marksmanship; hypovolemia; logical performance and work capacity uses a standard blood
physical capacity bank donation volume of 1 unit (450mL), or about 9% of
blood volume. Several physiological factors of performance
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are negatively affected by one unit of blood donation includ-
ing: VO max, cardiac output (Q), hemoglobin/hematocrit
Introduction 2
(Hb/Hct), temperature, time to exhaustion (TTE), and oxygen
Fresh whole blood (FWB) has been the standard of care for delivery (DO ). Each of these changes in performance affects
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the treatment of hypovolemia secondary to blood loss in the submaximal and maximal exercise differently. Additionally,
Tactical Combat Casualty Care guidelines since 2014. How- measures of blood lactate and hydration may also be of inter-
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ever, conventional Combat Medic Specialists (68W) are not est for performance after blood donation. 6
*Correspondence to Brian K. Schilling, UNLV, 4505 S. Maryland Parkway, Las Vegas, NV 89154 or brian.schilling@unlv.edu
1 MAJ Alex P. Houser, Lt. Col. Mario A. Soto, Paul G. Goldberg, Kevin J. Cronin, and SGT Rick C. Caldwell are affiliated with the U.S. Army
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Special Operations Command (USASOC). Kathryn S. Bell and Dr. Brian K. Schilling are affiliated with the Department of Kinesiology & Nu-
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trition Sciences, University of Nevada, Las Vegas, NV.
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