Page 28 - JSOM Fall 2025

Mitigating Heat Loss in IV Tubing
During Austere Blood Transfusions

1
Emine Foust, PhD *; Drew Homan 2

ABSTRACT
Background: Heat loss through intravenous (IV) tubing during collected in the blood bag is then administered to the trauma
a fresh whole blood (FWB) transfusion in austere environments patient through the intravenous tubing (IV) section of the kit.
4
can result in unhealthy fluid administration temperatures for However, when tested in austere environments, these transfu-
patients. This research study aimed to quantify the amount of sion kits experience several issues such as obstructed blood
heat loss through the IV tubing during austere blood transfu- flow, freezing and breakage of components, and condensation
sions and propose mitigation methods, such as utilizing ther- in the tubing. This research study focuses on the impact of
mal insulation around the IV tubing and reducing the overall low environmental temperatures and the associated heat loss
length of the tubing. Methods: Experiments were conducted in on the performance of the FWB transfusion kit, particularly
an environmental chamber where fluid temperature was con- through the IV tubing component.
trolled at the inlet of the IV tubing, while the resulting outlet
fluid temperatures and volumetric flow rates were measured. Heat loss may occur through the FWB transfusion kit’s IV
The temperature within the environmental chamber was sys- tubing and blood bag components. Analyzing fluid heat loss
tematically reduced by 3°C from the first collection starting at through IV tubing and blood bags, Singleton et al. reported
20°C to a final collection at –39°C. Results: Heat loss analysis that the most significant heat loss occurs through the IV tub-
revealed that 40.9 (SD 3.4) W of heat was lost, even when ing. Fluid heat loss through the IV tubing presents two poten-
5
the ambient temperature was 20°C. As the environmental tem- tial hazards to healthy blood transfusion. First, the IV tubing
perature reached –39°C, the heat loss through the IV tubing may impact delivery time when the fluid flow through the IV
increased to 168 (SD 17.4) W. Conclusion: Significant heat tubing varies. Blood viscosity increases at colder temperatures,
loss occurs through IV tubing during blood transfusions in corresponding to lower fluid flow rates. Obstructed flow of
6
cold austere environments. Mathematical models suggest that fluid through the FWB transfusion kit is harmful to the health
thermal insulation around the IV tubing and reducing overall of the trauma patient. At times, external pressurizing devices
tubing length could effectively mitigate these losses. are attached to the FWB transfusion kit to achieve higher flow
rates for more emergent patients. More commonly in less
Keywords: transfusion; fresh whole blood; IV tubing; heat loss; emergent situations, the blood bag is raised above the location
insulation; austere environments of infusion so that gravity motivates fluid flow. Ghosh and
Haldar recommend a 90–200mL/min flow rate for less emer-
gent, gravity-dependent situations. 7
Introduction
Second, fluids flowing through IV tubing can lose heat to the
Hemorrhagic shock is the leading cause of preventable death environment, particularly in cold conditions, resulting in a de-
on the battlefield. In 2014, TCCC Guidelines were updated crease in fluid temperature before entering the patient. Infu-
1
to recommend the use of fresh whole blood (FWB) in trauma sion of cold fluids may contribute to hypothermia, which is
treatment instead of component therapy. Results of a 2009 associated with impaired platelet function, reduced enzymatic
2
study found the 30-day survival rate to be 95% for trauma activity of the coagulation cascade, and ultimately, cold-in-
patients who received FWB compared to the 82% survival rate duced coagulopathy and impaired hemostasis. To mitigate
1
for trauma patients who received component therapy. These these risks, maintaining fluid temperatures within the normo-
data were collected from Special Operations units within thermic range (36.5–37.5°C) is critical during resuscitation
the United States Military which had been employing FWB and perioperative care, especially in austere environments
transfusion throughout the wars in Iraq and Afghanistan. In where environmental temperatures can significantly impact
3
response to the TCCC Guidelines change, conventional units fluid temperature. This temperature range is important be-
1,8
within the U.S. Military began adopting the same FWB trans- cause trauma patients with a core body temperature of less
fusion procedures as the Special Operations units. than 34°C are found to have a mortality rate of 40%. A core
body temperature of less than 33°C is associated with a 69%
Military units use the FWB transfusion kit prescreen and ros- mortality rate while a core body temperature of less than 32°C
ter the blood types of members of the unit so that blood can be is associated with a 100% mortality rate. In situations where
8
drawn from a matched donor within the unit using the blood the trauma patient is already hypothermic, transfusion fluids
bag and attached catheter component of the kit. The FWB should enter the body at temperatures between 40 and 42°C.
9
*Correspondence to foust.emine@westpoint.edu
2
1 Dr. Emine Foust and Drew Homan are affiliated with the Department of Mechanical and Aerospace Engineering, United States Military Acad-
emy, West Point, NY.
26