Page 44 - JSOM Summer 2019

comprised investigations of tourniquets as used by one com- FIGURE 1 Handrail simulates an infant limb for deliberate practice
petent user and one expert user. The expert designed the study of tourniquet use.
and also acted as a coach in deliberate practice of tourniquet
use.

The C-A-T, generation 7 was used, which has a band-and-rod
design. Each C-A-T is arranged in what is called the quick-
7–9
launch configuration, where the tourniquet’s self-adhering
band is already routed through the tourniquet’s buckle to fas-
ten to itself to form a loop. The loop is folded so that the tour-
niquet is compact. Individual tourniquets have instructions
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for use (IFU) inserted, and the tourniquet and instructions are
packaged together in shrink wrap. The study tourniquets were
unwrapped and IFU were removed. Individual users had their
specific tourniquet for deliberate practice.
The practice setup was designed to be demonstrably suitable
for a public user to practice on an everyday object instead of
on themselves or a manikin. The practice platform selected
was also to allow loop passage of the tourniquet so the band. An orange tourniquet was placed preliminarily on a handrail. The
Such passage avoids unrouting the band from the buckle tourniquet loop was passed from the user’s and viewer’s left side
and thereby also avoids a rerouting. The preparatory steps around the free end of the handrail. The self-adhering band is the main
component of the loop; the band remained routed through the buckle,
to the intended practice routine were meant to be simple, by the band was self-adhered between the two C-shaped clips, and the
requiring only that a configured tourniquet had to have the excess band dangled down toward the floor. The users easily tolerated
loop opened. This practice method may be ideal for a nov- this height during repeated practice uses. The handrail withstood me-
ice’s first use in learning. In each practice, the user picked up chanical loading in accordance with building codes.
the tourniquet, gripped it with both hands, pulled its folded Results
form apart to make a ripping sound as the loop opened up
into an oval shape, the loop was passed around the limb, and Results of Time to Apply a Tourniquet by Use Number
the tourniquet was applied. The instructional mantra was Each user applied their tourniquet repeatedly to a large limb,
“grip, rip, loop.” The passage was routine except the limb size and time results shortened, on average, with the accrual of
was small. experience (Figure 3). This expected finding occurred for both
users. The expert user had, on average, faster times, which
The item we chose to simulate a limb was a handrail in our indicated prelearning.
workplace. The steel handrail had its end free to loop passage.
The handrail circumference was 5.25 in., like an iPhone (mod- Ease of Use Results by Time to Apply a Tourniquet
els 5 or SE), and the tourniquet fit snugly around the limb Looking at those same applications for ease of use showed, on
(Figure 1). average, an association of more ease when less time was taken
to apply the tourniquet (Figure 4). This expected finding oc-
The bend in the stabilization plate of the tourniquet was nota- curred for both users. The expert user was, on average, faster
ble and the loop circumference became so shortened that the (27–108 seconds) and had easier use (range, 4–5). The time
plate abutted the buckle. In this small loop, the only modifica- the competent user took varied more widely (32–140 seconds;
tion needed in the instructions for use was to adhere the band ease-of-use scores, 2–5).
between the clips, because the only available fastener surface
to self-adhere the band was between the clips (Figure 2). The Ease of Use Results by Use Number
self-adhering surface was taken away by shortening the loop and Time of Application
to leave none available for adherence in the normal place, that Looking at those same applications for accruing experience,
is “all the way around the limb, but not over the rod clips.” the average of both users’ time decreased in a power law of
10
The only place available was between and past the clips, and practice (Figure 5). This expected finding of time decreases
such fastening impeded neither turning nor securing the rod. was accompanied by another expected finding: Experience, on
Each user conducted 100 practices. average, increased the ease of use. However, the magnitudes of
those changes were surprisingly large and similarly shaped and
Data recorded included ease of use (on a 5-point Likert scale, scaled through early, middle, and late uses. Notably, one trend
with 1 being very difficult, 2 difficult, 3 neutral, 4 easy, and was an inversion of the other, because the ease–time associa-
5 very easy), time to apply the tourniquet, and notable im- tion was negative. The directions of the association were as ex-
pressions of use. A smartphone was used as a timer. The user pected because application times went down as ease went up.
started the timer, gripped the tourniquet, ripped it, and looped Other surprises included that the changes were concurrent and
it before application. that the two trend lines arced away from each other as if the
change in ease was an inverted reflection of the change in time.
After collecting data, the expert used new tourniquets on
other limbs to map fits by girths (Table 1). Descriptive sta- Results of a Check of Fit on a Medium-Sized Pipe:
tistics were used to analyze the data and present results. A Workaround Technique
Analyses were performed using Excel 2003 (Microsoft, www In a stairwell, we found a pipe with a 4.25-in. circumfer-
.microsoft.com). ence, and the tourniquet fit that medium-sized simulated limb

42 | JSOM Volume 19, Edition 2 / Summer 2019