Page 50 - Journal of Special Operations Medicine - Spring 2017

Exposure to the environment was made by placing the the two users. Thus, both users performed 150 tests, 75
study group of tourniquets on the metal roof of a home tests each in the control and study groups.
in the center of San Antonio, Texas. The unexposed con-
trol group was stored in a climate-controlled laboratory. The order in which the devices were tested was random-
The two groups of tourniquets were purchased simulta- ized such that the control group and study group were
neously from the same lots and batches and were concur- assessed concurrently. User order was one at a time and
rently exposed or stored. The exposure began 3 July 2013 as allowed by the individual’s schedule. The scientist
and ended 2 January 2015 (i.e., 548 days, or 18 months). performed the first test, the cadet (user 2) made the next
150 tests, and the scientist finished with his 149 remain-
The three models of tourniquet studied were the Special ing tests.
Operations Forces Tactical Tourniquet in its wide ver-
sion (SOFTT-W; Tactical Medical Solutions; https://www The tourniquets were tested on a laboratory manikin
.tacmedsolutions.com), the Ratcheting Medical Tourni- that was designed to aid training by providing feed-
quet (RMT; M2 Inc.; http://www.ratchetingbuckles.com), back on user performance. The investigators used a
™
and the Generation 6 version of the Combat Application HapMed Leg Tourniquet Trainer (leg model 000F;
Tourniquet (C-A-T; Composite Resources; https://www CHI Systems; http://www.chisystems.com); a simulated
.narescue.com; Figure 1). C-A-T use was single-routed right-thigh with an above-knee amputation injury was
for the self-adhering band. the testing scenario. 10–13 The medial hip had an embed-
ded computer with a smartphone-like touchpad. Soft-
There were two tourniquet users—a scientist (user 1) ware integral to the thigh (version 1.9; CHI Systems)
and a cadet (user 2). Users had familiarization training allowed the manikin to stand alone and be operated by
in use of the manikin and with each model of tourni- user input through finger touch on the pad. The thigh
quet. The cadet was an undergraduate student from the was placed on a laboratory table and was operated in
US Military Academy and had been formally trained in accordance with the manufacturer’s instructions. The
C-A-T use, whereas the scientist was a tourniquet expert proximal thigh circumference of the manikin is 57cm
and had tourniquet experience in trauma care, executive (22.25in), representing a medium build for the simu-
consultation, and research and development. The scien- lated casualty; software calculations allow simulation
tist trained the student in the use of study tourniquets. of small, medium, or large circumferences. Tourniquets,
Tourniquet training included reading the instructions users, tests, and outcomes were uniquely identified.
for use, handling of each model, and one or two prac-
tice uses for each model on the manikin before testing The manikin thigh did not bleed, but bleeding was rep-
began. resented by red lights that transilluminated the wound.
The number of lights illuminated represented the bleed-
A total of 300 tests (replicates) were performed—150 ing rate: all 26 lights illuminated indicated uncontrolled
tests each in the control group and study group. A total bleeding, few lights blinking indicated intermediate con-
of 30 tourniquet devices were used overall in the study, trol, and no lights illuminated indicated bleeding had
with five devices per model allocated to both the study stopped. Pressures near the threshold required for ef-
and control groups (10 devices per model for the study fectiveness may teeter at, above, and below the thresh-
overall). Each device was tested five times by each of old in real time, just as in real patients; the lights may

Figure 1 Images of tourniquet models. (A) Special Operations Forces Tactical Tourniquet. (B) Ratcheting Medical Tourniquet.
(C) Combat Application Tourniquet. Image used with permission of North American Rescue.

(B)

(A) (C)

28 Journal of Special Operations Medicine Volume 17, Edition 1/Spring 2017