Page 48 - JSOM Spring 2023

The Effect of Prehospital Blood Transfusion on
Patient Body Temperature from the Time of
Emergency Medical Services Transfusion to
Arrival at the Emergency Department

1
Elizabeth M. Mannion, MD, FAAEM *; Ronald G. Pirrallo, MD, MHSA, FACEP ;
2
3
Aaron Dix, MBA, NRP ; Luke Estes, FP-C, NRP 4

ABSTRACT
Background: Transfusion of blood products is life-saving and prehospital hypothermia alone as an independent risk factor
time-sensitive in the setting of acute blood-loss anemia, and is for early death in critically ill patients. 4,5
increasingly common in the emergency medical services (EMS)
setting. Prehospital blood products are generally “cold-stored” Perhaps most commonly, hypothermia is considered within the
at 4°C, then warmed with a portable fluid-warming system for context of the “lethal triad,” a clinical condition additionally
the purpose of preventing the “lethal triad” of hypothermia, characterized by coagulopathy and acidosis. It is associated with
acidosis, and coagulopathy. This study aims to evaluate body increased risk of mortality. 1,2,6 Acute blood loss in the setting of
temperature changes of EMS patients receiving packed red trauma or non-traumatic hemorrhagic conditions leads to a vi-
blood cells (PRBC) and/or fresh frozen plasma (FFP) when us- cious cycle of hypoperfusion and acidosis. This, in conjunction
ing the LifeWarmer Quantum Blood & Fluid Warming System with rapid development of coagulopathy and thermoregulatory
(LifeWarmer, https://www.lifewarmer.com/). Methods: From instability, leads to further bleeding, portending to catastrophic
1 January 2020 to 31 August 2021, patients who qualified for outcomes. Proper resuscitative management in the prehospi-
1,2
and received PRBC and/or FFP were retrospectively reviewed. tal setting involves volume expansion with an oxygen carrying
Body-temperature homeostasis pre- and post-transfusion were fluid to sustain tissue perfusion, as well as the delivery of clot-
evaluated with attention given to those who arrived to the ting factors to replace those lost due to hemorrhage. 2
emergency department (ED) hypothermic (<36°C). Results:
For all 69 patients analyzed, the mean initial prehospital tem- Based on successful outcomes in the combat setting, civilian
perature (°C) was 36.5 ± 1.0, and the mean initial ED tempera- ground EMS systems are increasingly establishing blood-
ture was 36.7 ± 0.6, demonstrating no statically significant transfusion programs. Wheeler et al. noted within a retrospec-
change in value pre- or post-transfusion (0.2 ± 0.8, p = .09). tive review that patients transfused with non-warmed blood
Shock index showed a statistically significant decrease follow- before arrival to the hospital were more likely to be hypothermic
ing transfusion: 1.5 ± 0.5 to 0.9 ± 0.4 (p < .001). Conclusion: (<35°C). Prehospital blood products are generally “cold-
7
Use of the Quantum prevents the previously identified risk of stored” at 4°C, then warmed with a portable fluid warming

hypothermia with respect to unwarmed prehospital transfu- system. Alone, cold-stored blood can lower core body tem-
8
sions. The data is favorable in that body temperature did not perature by 0.5–1°C per 500mL administered. Previous stud-
8
decrease in critically ill patients receiving cold-stored blood ies implicate non-warmed prehospital IV fluids and blood
warmed during administration with the Quantum. products as a risk factor for developing hypothermia. Ther-
7,9
modynamic modelling shows the major beneficial effect of ac-
10
Keywords: prehospital blood transfusion; lethal triad; dam- tive fluid warming is the prevention of further net heat loss.
age-control resuscitation; tactical combat casualty care Inline blood warmers, such as the Quantum used in this study,
aim to warm the transfusing blood to a normothermic range
≥36°C. The goal is to decrease the temperature differential
between the transfusing blood and patient temperature to ul-
Introduction
timately prevent unintended hypothermia. As EMS blood pro-
Prehospital hypothermia, generally defined as a core tempera- tocols become more common, an evidence-based evaluation
ture <36°C, is frequently observed in victims of trauma. Al- of temperature management during prehospital blood transfu-
1,2
though primary hypothermia is defined by core temperatures sion is imperative to guide appropriate patient care.
<35°C, secondary hypothermia associated with trauma is con-
sidered at temperatures <36°C and is reflected in the current Published data on body-temperature maintenance following
Tactical Combat Casualty Care guidelines. As early as the prehospital blood transfusions is lacking. In this retrospec-
3
American Revolutionary War, hypothermia had been identi- tive case series analysis, the authors primarily seek to identify
fied as a detriment to the clinical recovery of soldiers suffer- how body temperature is affected when using the Quantum to
ing traumatic injuries. More recent literature has described transfuse PRBC and/or FFP in the prehospital setting.
*Correspondence to elizabethmmannion@gmail.com
1 Dr Elizabeth M. Mannion and Dr Ronald G. Pirrallo are physicians affiliated with the Department of Emergency Medicine, Prisma Health-
2
Upstate, and are both Clinical Assistant Professors at the USC School of Medicine-Greenville, Greenville, SC. Aaron Dix is the executive director
3
of Prisma Health Ambulance Service, Prisma Health, Greenville, SC. Luke Estes is the Manager of Mobile Integrated Health at Prisma Health
4
Ambulance Service, Greenville, SC.
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