Page 12 - JSOM Winter 2022

FSEs, carry limited quantities of cold (1–6°C) low-titer O whole FIGURE 1 Search flow diagram.
blood (LTOWB). Second, the Joint Trauma System (JTS) Clin-
ical Practice Guidelines (CPGs) recommends warming blood
1
products to 37°C for transfusion. This recommendation is
secondary to battlefield casualties being the most susceptible
to hypothermia due to prolonged evacuation times, significant
injury patterns, altered intrinsic thermoregulation abilities,
and environmental factors. Finally, cold blood administration
would further influence a casualty to enter the triad of death,
defined as hypothermia, coagulopathy, and acidosis. Profound
hypothermia affects the triad of death by worsening coagulop-
athy, decreasing drug elimination, and increasing overall hem-
orrhage. Therefore, to mitigate the deleterious effects of cold
blood administration, the far forward employment of bat-
tery-operated IV fluid warmers is often used for early blood
administration in patients that require resuscitation.

In March 2019, the US FDA issued a Class 1 recall on en-
Flow cartridges manufactured from January 2016 to March
2
2019. Testing demonstrated aluminum elution from enFlow
cartridges into IV solutions, thereby exposing patients to po-
3,4
tentially unsafe aluminum levels. Despite this FDA recall, the published two articles that demonstrated uncoated disposable
enFlow delivery system and its components remain assigned to aluminum heated plates elute aluminum into IV fluids. The
3,4
FSEs, SOF units, and aeromedical units. FDA subsequently announced a Class 1 recall on enFlow car-
tridges manufactured from January 2016 to March 2019. The
2
This literature review seeks to determine the ideal portable Thermal Angel and Buddy Lite do not use uncoated aluminum
battery-operated IV fluid warmer (Buddy Lite, enFlow, Ther- heated plates. See Figures 2, 3, and 4 for device photographs
mal Angel) for trauma patients undergoing massive blood
transfusions in austere settings. Additionally, the authors pro- FIGURE 2 enFlow with battery accessory.
vide a risk mitigation analysis for the enFlow delivery system.

Search Strategies
The authors systematically searched the following databases:
EBSCO, Google Scholar, MEDLINE PubMed, AHRQ EPC
Evidence Reports, Cochrane Databases, Dynamed Plus, De-
fense Technical Information Center (DTIC), Federal Research
in Progress, Evidence-Based Medicine Reviews, Military and
Government Collection, and the New England Journal of
Medicine. The search included the following MeSH terms and
key words: portable fluid warmers, Buddy Lite, enFlow, Ther-
mal Angel, blood warmer, and military massive transfusion.
The authors also searched gray literature, to include the JTS
Quarterly, which features literature reviews pertaining to com- FIGURE 3 Buddy Lite.
bat casualty care.

Thirteen articles met the screening criteria. Four subject matter
experts in deployment medicine independently graded ten ar-
ticles with the Joanna Briggs Institute Critical Appraisal Tool.
After independent appraisal, a unanimous decision determined
if an article was included or excluded. The experts excluded
two articles from this literature review: one article due to the
inability to obtain a full-text copy while deployed, and the other
due to its exploration of the mathematical energy requirements
to treat hypothermia, rather than clinical applications for por-
table IV fluid warmers. See Figure 1 for search flow diagram.

Review of Literature
The authors operationally defined criteria for an ideal mas-
The physical characteristics and heating elements are unique sive blood transfusion based on flow rate, output temperature,
for each device. The following weights are a sum of the unit, and blood product amount. Ideal flow rates should approach
battery, and priming volumes for each delivery system: enFlow 100mL/min, which approximates maximum crystalloid flow
(3.04 lb), Thermal Angel (2.16 lb), and Buddy Lite (1.69 lb). rates through a 1¼-in-length, 18-gauge peripheral intravenous
The enFlow uses an uncoated disposable aluminum heated (PIV) catheter (BRAUN, Introcan Safety, https://www.bbraun
plate to warm IV fluids. In 2019, the Anaesthesia Journal .com/en/products/b/introcan-safety.html). Deployed medical

10 | JSOM Volume 22, Edition 4 / Winter 2022