Page 25 - JSOM Winter 2023

understanding with a Tac RMT; and a combination of not Application Process Scoring: Tourniquet Security
fully understanding the strap system and the tightening sys- Tourniquets that involved applier actions for strap/redirect
tem and giving up on tightening too soon with an RST. One and/or tightening-system security had higher rates of security
applier with some experience had one occlusion failure: a lack problems than did tourniquets with both self-securing strap/
of SOFTTW3 strap pulling leading to six turns of the windlass redirect and self-securing tightening systems (p<.0001; Figure
without occlusion; with this many windlass turns, it is unclear 2 tourniquet security, Figure 3D, and Figure 4).
that anyone could have increased the number of turns to reach
occlusion and then secured the rod. Three appliers with no Application Process Scoring:
experience had two occlusion failures each: one applier lack of Combined and Critical Strap/Redirect-System,
tightening-system understanding with a CAT7 and SOFTTW3; Tightening-System, and Tourniquet Problems
one applier lack of tightening-system understanding with a Problems were frequent with strap/redirect systems (Figure
CAT7 and TMT; and one applier lack of strap-system under- 6A; p<.0001), but not all problems had the same importance.
standing with a Tac RMT and lack of strap pull leading to The frequency of strap/redirect major understanding problems
running out of ladder teeth with an RST. Four appliers with no varied (Figure 6B; p<.0001). The two strap/redirect-system
experience had one occlusion failure each: lack of strap-system outcomes associated with the critical final outcomes of occlu-
understanding with one SOFTTW5 (broke slider with reth- sion and tourniquet security varied across tourniquets (Figure
reading failure), two Tac RMTs (rethreading failures), and one 6C; p<.0001) and did not match the frequency of either any
X8T (pulled at the secondary redirect). strap/redirect-system problems or strap/redirect-system major
understanding problems (p<.0001 for each tourniquet). De-
Application Process Scoring: spite conceptual similarities such as a clip, a simple redirect
Tightening-System Securing Struggle buckle, a slider redirect buckle, or a hook-and-loop strap,
Self-securing tightening systems had no securing struggles conceptually similar strap/redirect systems did not match each
(p<.0001 versus non-self-securing tightening systems, Figure 2 other regarding strap/redirect problem frequencies (for exam-
securing struggle). Forty appliers struggled securing windlass ple, compare CAT7 and OMT and SOFTTW3 and SOFTTW5
rods in 58 of 254 applications: 23 TMT, 22 SOFTTW3, 11 in Figure 6C).
SOFTTW5, and 2 CAT7 (p<.0001 across windlass rod tour-
niquets, Figure 2 securing struggle). Use of the SOFTTW3 Tightening-system problem frequencies varied (Figure 6D;
triangle was associated with more rod-securing difficulties p<.0001). Despite conceptual similarities such as a ratcheting
than use of the SOFTTW5 bracket (p=.0385). (Bracket-only buckle advancing on a ladder, conceptually similar tighten-
securing is not medically appropriate and was only allowed to ing systems did not match each other regarding tightening-
assess difficulty imposed by the triangle; only 10 struggled of system problems (for example, compare OMT, Tac RMT, and
59 appliers who just used the SOFTTW5 bracket.) Across all RST in Figure 6D). The tightening-system problem associated
windlass rod tourniquets, suboptimal strap tightness was asso- with the critical final outcome of tourniquet security varied
ciated with struggling to secure the rod (p<.0001). Struggling across non-self-securing windlass rod tourniquets and did
frequency was not significantly different by applier-tourniquet not exist with self-securing ratcheting tourniquets (Figure 6E;
experience (18 any experience versus 22 no experience appli- p<.0001). The frequency of system-security problems was
ers [p=.61] with 24 versus 34 applications [p=.23]). not significantly different from the frequency of the com-
bined tightening-system problems for the CAT7, X8T, and
Application Process Scoring: Tac RMT (each p >.50) but was different for the other tourni-
Tightening-System Security quets (SOFTTW3, SOFTTW5, and RST each p<.0001; TMT
Self-securing tightening systems had no security problems p=.0041, OMT p=.058).
(p<.0001 versus non-self-securing tightening systems, Figure
2 tightening security). Only two of the 45 CAT7 rod-security The critical tourniquet application problems of lack of occlu-
problems involved failure to put the rod into the bracket (one sion or lack of security are combined in Figure 6F (p<.0001).
applier used the time strap to attach the rod to the bracket top, Tourniquets relying on applier actions for strap/redirect- system
another rested the rod against the edge of the bracket opening), security have a higher frequency of security problems. For
two involved placing the limb-encircling strap in the bracket each tourniquet other than the CAT7, the problem frequen-
before the rod, 18 involved placing neither the limb-encircling cies were different for critical tourniquet application problems
strap nor the time strap over the rod, six involved placing only (Figure 6F), strap tightness and/or security problems (Figure
the limb-encircling strap over the rod, 11 involved placing only 6C), and tightening-system security problems (Figure 6E;
the time strap over the rod, and nine involved placing the time p<.0001). For the CAT7, the frequency of critical tourniquet
strap over the rod and then trying to place the limb-encircling application problems (Figure 6E) was different from strap
strap over the time strap. With the SOFTTW3, one applier was tightness and/or security problems (Figure 6C; p<.0001) but
physically unable to secure the rod in the triangle with two rod was almost the same as that for tightening-system security
turns (Figure 5); one rested the rod on the edge of the triangle problems (Figure 6E).
with three rod turns; and one rested the rod on the redirect clip
with three rod turns. With the TMT, 13 appliers placed the rod Discussion
under the first part of the bracket without clicking it into the
secure location; one balanced the rod on the open side of the The key findings were as follows: 1) Conceptually similar de-
bracket without placing it under the first part of the bracket, sign features did not result in matching problem frequencies;
four balanced the rod on the wrong side of the bracket, and a 2) Because the initial occlusion can be transient, 40,41 not al-
design problem prevented one applier from correctly securing lowing timed appliers to do any additional tightening af-
the rod in the bracket with four rod turns (Figure 2 open red ter they have called “Done” is likely to result in quite a few
circles and Figure 3E). non- occlusive applications that could easily be tightened to

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