Page 42 - Journal of Special Operations Medicine - Spring 2015

Laboratory Testing of Emergency Tourniquets
Exposed to Prolonged Heat

John P. Davinson, MS, PA-C; John F. Kragh Jr, MD;
James K. Aden 3rd, PhD; Robert A. DeLorenzo, MD; Michael A. Dubick, PhD

ABSTRACT
Background: Environmental exposure of tourniquets has hemorrhage, and they are intended for use on the battle­
been associated with component damage rates, but the field by Warfighters or out­of­hospital medics. Most
4,5
specific type of environmental exposure, such as heat, is emergency tourniquets are of a windlass­and­strap de­
unknown. Emergency­tourniquet damage has been asso­ sign. Use of this type of tourniquet is easy to learn, and
6,7
ciated with malfunction and loss of hemorrhage control, civilians have been encouraged to use them. 5
which may risk loss of life during first aid. The purposes
of the study are to determine the damage rate of tourni­ The recent wars in Southwest Asia were often fought in
quets exposed to heat and to compare the rate to that deserts, and the summers in Iraq, Afghanistan, and Ku­
of controls. Methods: Three tourniquet models (Com­ wait are particularly hot; for example, the record high
bat Application Tourniquet ; SOF Tactical Tourniquet; temperature in the shade in Baghdad, Iraq, in July is
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Ratcheting Medical Tourniquet ) were tested using a man­ 50.0°C (122°F). In transport or in storage, supplies such
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ikin (HapMed Leg Tourniquet Trainer; www.chisystems as tourniquets can be exposed to heat for prolonged pe­
.com) that simulates extremity hemorrhage. The study riods. Metal shipping containers (also known as con­
group of 15 tourniquets (five devices per model, three tainer express [conex] boxes, which can be moved from
models) was exposed to heat (oven at 54.4°C [130°F] ship, to rail, and to truck without unloading or reloading
for 91 days), and 15 tourniquets similarly constituted the contents) may sit outside for months or years, thereby
control group (unexposed to heat). Damage, hemorrhage exposing internal supplies to high temperatures. Investi­
control, distal pulse stoppage, time to effectiveness, pres­ gators have associated environmental exposure of mili­
sure (mmHg), and blood loss volumes were measured. tary tourniquets with damage rates of the tourniquet’s
Results: Three tourniquets in both groups had damage components, including the slot in the stabilization
8,9
not associated with heat exposure (p = 1). Heat expo­ plate that allows the band through, the self­adhering
sure was not associated with change in effectiveness rates band, and the friction adaptor.
(p = .32); this lack of association applied to both hemor­
rhage control and pulse stoppage. When adjusted for the The exact type of environmental exposure, such as heat
effects of user and model, the comparisons of time to ef­ or ultraviolet light, has not been specified as the culprit
fectiveness and total blood loss were statistically signifi­ for such damage, as no laboratory evidence is available
cant (p < .0001), but the comparison of pressure was not that relates, for example, heat exposure with compo­
(p = .0613). Conclusion: Heat exposure was not associ­ nent damage rates. To better understand the risk of
ated with tourniquet damage, inability to gain hemor­ tourniquet damage due to environmental exposure, we
rhage control, or inability to stop the distal pulse. designed an experiment to ascertain damage rates with
and without prolonged heat exposure. The purpose of
Keywords: tourniquets, hemorrhage, resuscitation, medical the study was to determine the damage rate of tourni­
device, injuries and wounds quets exposed to heat and compare the rate to that of
a control group of tourniquets. Secondary goals were
to explore the relationship of various factors, such as
tourniquet efficacy and heat exposure.
Introduction
In the US Military services during the recent wars in Iraq Methods
and Afghanistan, tourniquets were a means of last re­
sort, and, in 2005, they became a means of first aid. In A US Army Institute of Surgical Research laboratory
1
2005, the US Military fielded tourniquets widely on the protocol was approved, and the experiment was con­
battlefield. The tourniquets are designed for mechani­ ducted according to the protocol. An experiment was
2,3
cal compression of extremities to control posttraumatic designed to compare the function of tourniquets with

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