Page 17 - JSOM Winter 2024

Future studies may involve ice replacement in the coolers; we stored on the battlefield enable safe and effective delivery of
hypothesize that replacing ice periodically may prolong the combat casualty care.
1–6°C range for an unlimited period, assuming the availability
of ice. Importantly, the size and weight of the cooler make Conclusion
transportation across large distributed maritime operations
more feasible. While aviation significantly decreases transport This brief evaluation demonstrated the reliability of commer-
time across geographically disparate regions, real-world mil- cially available passive refrigeration (a cooler) for the storage
itary logistics often results in prolonged transportation. This of blood products. This may enhance blood storage capabil-
may occur in poorly climate-controlled environments (e.g., ity in austere, disaster, and operational military environments.
exposed on the tarmac of an airfield). Blood products are a The ability to reliably store blood between 1 and 6°C with
critical piece of combat casualty care, and ensuring adequate only a cooler and ice may dramatically expand where and
blood supply over long distances is a critical component of when blood products can be given. Further evaluation, includ-
medical logistics in distributed maritime operations. ing the possibility of prolonged blood storage, may be reason-
able to consider. The feasibility and simplicity of the passive
A major limitation of this system is the availability of ice. system may allow blood products to be available as close to
Many local economies provide sources of adequately refriger- the point of injury as possible, without concern for waste, in
ated ice. Such sources can be found in many expeditionary ad- temperature-regulated environments.
vanced operating base formats and irregular/unconventional
warfare settings if positioned adjacent to an even marginally Author Contributions
developed society. However, disaster areas may not have ac- SH, JK, AB, JC, YI, AH, TN, and KC contributed equally to
cess to clean water and electricity. Blood products are stored the conception, manuscript development, and final approval
in sealed bags with theoretically two separate layers of pro- of the manuscript. SH, AB, JC, and KC contributed equally to
tection against contaminants. The presence of Escherichia coli the background and analysis of the manuscript.
or other pathogens in dirty water may contaminate the blood
products—this theory remains untested but is a concern for Disclaimer
the authors. Similarly, the lack of electricity is a critical limita- The views expressed in this article are those of the authors
tion for using the passive cooler. Generators may help offset and do not necessarily reflect the official policy or position of
some of the risks, but the generators may not necessarily be the Department of the Navy, Department of Defense, or the
colocated with ice makers. The absence of electricity is also a United States Government.
major limitation of the active cooling systems, requiring the We are military Servicemembers. This work was prepared as
batteries to be charged at regular intervals.
part of our official duties. Title 17 U.S.C. 105 provides that
“Copyright protection under this title is not available for any
As well, specific analytical chemistry domains represent mi- work of the United States Government.” Title 17 U.S.C. 101
nor—but nonzero—failure modes in this study. First, differ- defines a United States Government work as a work prepared
ences in heat transfer characteristics of the sample used (0.9% by a military Servicemember or employee of the United States
saline, R=4.178 kJ/Kg°K) and whole blood (R=3.84 kJ/Kg°K), Government as part of that person’s official duties.
may result in more favorable measured performance of this re-
frigeration strategy than would be observed if whole blood was This study has received institutional clearance.
used. Saline, being more parts water than blood, has an 8.4%
higher heat transfer coefficient than whole blood, permitting Disclosures
saline to absorb more heat than blood before demonstrating The authors have nothing to disclose.
a change in temperature. Next, this study assumes uniform
temperature throughout the refrigeration space to generalize Funding
the temperature at the location of the thermometer to be the No funding was received for this work
surface temperature of the simulated blood products. It is not
reasonable to postulate a means to quantify the effects of this References
assumption on study conclusions, and such speculation is likely 1. Kotwal RS, Scott LLF, Janak JC, et al. The effect of prehospital
negligible. However, that commercial blood coolers employ transport time, injury severity, and blood transfusion on survival of
blood product dispersion and convective cooling should imply US military casualties in Iraq. J Trauma Acute Care Surg. 2018;85
(1S Suppl 2):S112–S121. doi:10.1097/TA.0000000000001798
that this would have a nonzero effect on these results. 2. Gurney JM, Staudt AM, Del Junco DJ, et al. Whole blood at the tip
of the spear: a retrospective cohort analysis of warm fresh whole
Finally, when discussing the storage of blood products in a blood resuscitation versus component therapy in severely injured
combat environment, it is important to consider the limita- combat casualties. Surgery. 2022;171(2):518–525. doi:10.1016/j.
tions of frozen packed red blood cells (pRBCs). When pRBCs surg.2021.05.051
undergo freeze-preservation, these blood products can be 3. Gurney J, Staudt A, Cap A, et al. Improved survival in critically
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effectively stored for over 10 years. Although shelf-life in- injured combat casualties treated with fresh whole blood by for-
ward surgical teams in Afghanistan. Transfusion. 2020;60(Suppl
creases substantially with freezing relative to cold-chain stored 3):S180–S188. doi:10.1111/trf.15767
blood, frozen pRBCs require sustained storage at –80°C with 4. Levin D, Zur M, Shinar E, et al. Low-titer group O whole-blood
specialized equipment to thaw and deglycerolize the blood resuscitation in the prehospital setting in Israel: review of the first
product; neither frozen storage assets nor deglycerolizing 2.5 years’ experience. Transfus Med Hemother. 2021;48(6):342–
equipment is readily available on the battlefield. Additionally, 349. doi:10.1159/000519623
activating blood for use from a frozen state may take 30–40 5. Shackelford SA, Gurney JM, Taylor AL, et al. Joint Trauma Sys-
tem, Defense Committee on Trauma, and Armed Services Blood
minutes per unit of pRBCs. Given these limitations, blood Program consensus statement on whole blood. Transfusion. 2021;
product solutions that are both ready-to-transfuse and easily 61(Suppl 1):S333–S335. doi:10.1111/trf.16454

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