Page 39 - JSOM Summer 2018

FIGURE 1 The two tested tourniquet models. FIGURE 3 Test setup.

The photograph shows the tested tourniquets: SAM Extremity Tourni-
quet (left) and the Combat Application Tourniquet (right), as the new
(study) and established (control) model, respectively.
The first aid kit and manikin were laid out on a table.
FIGURE 2 Layouts of two models of limb tourniquet.
the user wore safety glasses, and stood two steps and faced away
from the table until the assessor said, “Start.” The user turned,
stepped to the table, decided to use a tourniquet, unzipped the
kit, grasped and donned examination gloves, unwrapped the
tourniquet, unrouted the band by removing it from its course
through the buckle, and applied the tourniquet to the manikin.
The user could troubleshoot problems. After the user judged the
test as completed satisfactorily, including securing the rod and
recording the time of day, the user said, “Done.” The assessor
pressed the button to stop the manikin and test.

The manikin was previously described. Briefly, a HapMed
16
Leg Tourniquet Trainer (CHI Systems, http://www.chisystems.
com) simulated a limb amputation. The scenario included a
single patient (large adult), standard first aid, placement 2–3
in above the wound, feedback off, and bleed-to-death time of
240 seconds.
The two models are laid out on a desk with the Combat Application
Tourniquet at top and SAM Extremity Tourniquet at bottom. The manikin measured total trial time and time to determi-
nation of bleeding control. The manikin determined patient
and two military cadets. The scientist oriented users to the status (bleeding, stable, or dead), trial status (go [satisfactory]
study procedures. First, the user unrouted the band, laid the or no go), tourniquet placement, pressure, and blood loss. The
tourniquet flat on the table, and went over the names and user judged ease of use, turn number, bleeding control (by vi-
functions of the component with the scientist. Then the user sual inspection), and whether the distal pulse was stopped (yes
reconfigured the tourniquet for one-handed use. The user fol- or no by digital palpation). The assessor determined don time
lowed written and video instructions for tourniquet use and (start through donning gloves), unwrap time (grasp tourniquet
for one or two uses on the manikin. After each use, the user to tourniquet placement), and checked whether the user as-
unclipped the rod, peeled back the band, removed the tourni- sessed for bleeding control and pulse stoppage.
quet from manikin, pulled the tourniquet out to length, reset
the SXT prongs, and reconfigured the tourniquet. After each test, the assessor and user recorded data, noted find-
ings, and then discussed problems, such as damage to a tourni-
An assessor aided the users. The scientist was the assessor ex- quet or to the manikin, and user symptoms, such as tiredness.
cept when he was the user, and this was when the associate
took the assessor role. The assessor started and ended tests, Data were entered into a spreadsheet. From these data, the fol-
ran a stopwatch, and assessed performance. Users were to lowing were calculated: pretime (sum of don time and unwrap
think out loud and the assessor was to be silent during tests. time), posttime (total trial time minus time to determination of
bleeding control), and bleeding rate (blood loss volume divided
Test order was randomized by model. Each of the four us- by time to determination of bleeding control). Logic functions
ers performed 20 tests of each of the two models, for a total were made for effectiveness (patient status was marked as yes
of 160 tests. Tourniquets were stowed in a first aid kit laid if stable or no if patient status was either bleeding or dead)
on a table (Figure 3). The kit had the model to be tested, a and for composite score (sum of counts of satisfactory results
pair of gloves (acrylonitrile; Halyard Health, http://www among seven parameters: time to determination of bleeding
.halyardhealth.com/solutions/infection-prevention/medical control 120 seconds or less, go trial status, ease of use neu-
-exam-gloves.aspx), a marker pen, and a roll of 1-in cloth tape tral or better [i.e., score 3, 4, or 5], no manikin damage, no
(Durapore; 3M, https://www.3m.com). To simulate caregiving, user symptoms, and turn number fewer than four). Additional

Tourniquet Models Compared | 37