Page 50 - JSOM Fall 2025

Tourniquet Applications Knowledge-of-Results Feedback
In this paper, references to first and last tourniquet applica- Researchers did not provide any intentional feedback to ap-
tions indicate data from an experienced or no-experience ap- pliers. The evaluated items expected to involve a considerable
plier’s first tourniquet application and last pair of applications degree of intrinsic knowledge-of-results feedback were strap/
(combined seventh and eighth tourniquet applications). redirect understanding, tightening-system understanding, and
occlusion at “Done.” The items expected to lack intrinsic
The dorsal pedal artery Doppler signal was audible before knowledge-of-results feedback were idealness of hook-and-
starting applications. A wound was visually indicated on the loop strap security and idealness of windlass-rod security
distal aspect of the recipient’s thigh. Each application was (considered to have some, but limited, knowledge-of-results
videoed from two angles with GoPro Hero 5 Sessions (GoPro feedback).
Inc., San Mateo, CA). The collected videos were used for as-
sessments and timing of application processes. Statistical Analysis
2
1,2
To control for order effects, the orders of watching application
Full definitions of the major processes groupings, descriptions videos 4–11 and of tourniquet applications were separately ran-
of the processes scoring criteria, and descriptions of the pro- domized with 8×8 Latin Squares using hamsterandwheel.com
cesses timing are present in the text and appendices of refer- (a random Latin square generator). Time data were orga-
ences 1 and 2. Briefly: nized in Excel for Microsoft 365 MSO (Version 2508 Build
®
16.0.19127.20082 64-bit; Microsoft Corp., Redmond, WA).
– Minor understanding problems with strap/redirect systems Graphing and statistical analyses were performed with Graph-
were the following: delayed recognition of clip if present, Pad Prism, version 7.04 for Windows (GraphPad Software,
delayed recognition of correct strap pulling location, time Boston, MA). One-way analysis of variance (ANOVA) with
spent considering what to do with the length of strap pulled Sidak’s multiple comparisons tests was used for time compari-
through the self-securing redirect buckle, holding the strap sons of first experienced versus first no-experience, first expe-
tight while using the tightening system, and minor hook- rienced versus last experienced, first no-experience versus last
and-loop issues other than failure to completely open all no-experience, last experienced versus last no-experience and
the strap, pull interference, or inadequate circumferential with Tukey’s multiple comparisons test was used for time com-
wrapping. parisons of first versus second versus third encounters. Paired
– Major understanding problems with strap/redirect systems t tests were used for time comparisons of first versus second
were trying to unthread a clip redirect, concept problems encounters. Fisher’s exact tests were used for contingency table
rethreading redirects, and major hook-and-loop issues other comparisons.
than failure to completely open all the strap, pull interfer-
ence, or inadequate circumferential wrapping. Results
– Hook-and-loop strap security was inadequate if circumfer-
ential engagement was not continued around the limb or if Appliers
side-to-side engagement was <2/3 strap width. Of 64 source-study appliers, 10 were experienced and 33
1,2
– Understanding problem with the tightening system was a lack were no-experience. Applier numbers are source-study sub-
of understanding of how to use it to tighten the tourniquet. ject numbers. Of experienced appliers, two had experience
1,2
– Windlass-rod security was inadequate if it was incorrect with all eight tourniquets (least experience with X8T and
according to training videos, such as failure to include dual RST, #1 and #6); three had experience with CATs, SOFTTW3,
strap coverage over the CAT7 rod and failure to click the OMT, and Tac RMT (#2, #4, and #51); one had experience
TMT rod completely into the securing bracket. with CATs, SOFTTW3, and Tac RMT (#47); one had expe-
rience with CATs and RMTs (#54); and three had extensive
Times experience only with the OMT (#3, #7, and #11). Except for
Maximum application time allowed was 300 seconds. The one medical CAT use by #47, tourniquet experience in the ex-
time segments in this study were from the director saying “Go” perienced group was research, military training, or teaching
to the applier reaching strap security (“strap secured”) and related.
from the applier touching the tightening system after “strap
secured” (“touch tightening system”) to either saying “Done” Discrete Tourniquet Applications
or being stopped by the director (Figure 2). Figure 3 shows first and last application flow diagrams of each
tourniquet by each experienced or no-experience applier.
FIGURE 2 Timeline.
"Touch Times
"Strap Tightening Figure 4 shows times from “Go” to “strap secured” and from
Events: "Go" Secured" System" "Done"
“touch tightening system” to “Done” for first and last appli-
Timed cations by experienced versus no-experience appliers. Me-
Segments: "Go" to "Strap Secured" "Touch Tightening System" to "Done"
dian times from “Go” to “strap secured” were slowest for
This figure shows the time segments used for time comparisons between first applications by no-experience appliers and fastest for
tourniquet applications. last applications by experienced appliers (median times: first
no-experience 37.52 seconds, last no-experience 28.19 sec-
Times of 300 seconds were used for strap/redirect-system onds, first experienced 24.87 seconds, last experienced 24.53
event failures and for tightening-system event failures. No seconds; p=.008 first no-experience versus last no-experience,
times were assigned for processes following a system event p=.089 first no-experience versus first experienced, p>.847
failure (i.e., if a strap/redirect-system event failure occurred, first experienced versus last experienced, and last experienced
tightening-system use could not be timed or evaluated). versus last no-experience).

48 | JSOM Volume 25, Edition 3 / Fall 2025