Page 21 - JSOM Winter 2023

hook-and-loop interactions: while setting up to pull; during tightness (32 of 34 CAT7, 28 of 38 OMT, 20 of 33 SOFTTW5,
placement around the leg (two applications); side-to-side en- 16 of 39 RST, 10 of 38 SOFTTW3, 9 of 36 X8T, 3 of 16 Tac
gagement during pulling; repeated strap engagement distal to RMT, and 8 of 44 TMT; p<.0001 for differences across all tour-
the pulling hand requiring strap disconnection for the next niquets [Figure 2 pull technique and strap tightness]). Among
pull; and major side-to-side folding of the strap together during applications with good pull technique, simple redirects had the
pulling so that <2/3 overlap during strap securing. OMT diffi- highest number reaching optimal pull-related strap tightness
culties were strap side-to-side engagement during pulling. (27 of 28 CAT7, 22 of 26 OMT, 21 of 30 SOFTTW5, 13 of 25
SOFTTW3, 18 of 44 Tac RMT, 8 of 20 TMT, 8 of 25 RST, and
Tourniquet slipping around the limb during strap pulling was 6 of 28 X8T; p<.0001 for differences across all tourniquets
indicated by a major change in the redirect buckle location in [Figure 2 pull technique and strap tightness]). Not reaching
30 applications (5.9% of all applications: 7 RST, 6 Tac RMT, optimal pull-related strap tightness was associated with never
5 X8T, 3 CAT7, 3 OMT, 2 SOFTTW3, 2 SOFTTW5, 2 TMT; reaching occlusion (24 of 28 never occluded versus 231 of 476
slipping not shown in Figure 2). Only 10 of 30 applications occluded at some point in time; p=.0001) and with not being
with slipping reached optimal strap tightness (p=.089) versus occluded at “Done” (53 of 60 not occluded at “Done” versus
239 reached optimal tightness of 474 scorable for strap tight- 202 of 444 occluded at “Done”; p<.0001 [Figure 4]).
ness with no slipping. Many applications with slipping involved
more than one holding-against-slipping location: 12 involved No clip problems and no strap backsliding occurred during
locations pre-defined as bad (redirect buckle or rod), 8 involved tightening-system use. When correctly threaded, self- securing
no holding location, and 22 involved locations pre-defined as redirects successfully secured straps (p<.0001 versus non-
good (rod-securing bracket, hand flat on tourniquet above the self- securing redirects; Figure 2 strap security). Twenty-eight
redirect buckle, the X8T dial, or the Tac RMT holding loop). appliers failed to fully adhere hook-and-loop straps in 47 ap-
plications (Figure 2 strap security and Figure 4). Failure to fully
Strap-pulling effort (strong 352/weak 160 applications), major adhere consisted of not securing the entire circumference of
body weight engagement during pulling (major body weight exposed hook-and-loop (14 OMT, 7 TMT, and 5 CAT7), <2/3
175/primarily arms 337 applications), and visual assessment side-to-side overlap of hook-and-loop (12 TMT, 11 OMT, and
of strap tightness (tight 284/not very tight 228 applications) 4 CAT7), or failure to fully open the hook-and-loop (2 TMT;
before tightening-system use were all deemed difficult to score Figure 2 open red circles). Audible hook-and-loop releasing
consistently, and therefore were not used for assigning good or noise during tightening-system use occurred in the two never
bad pull technique in Figure 2. Assigning a single angle of strap fully opened TMT applications and one OMT application that
pulling was also difficult because the angle sometimes changed lacked full circumferential and side-to-side hook-and-loop
during pulling, and some applications had more than one pull, overlap. In the OMT application, the noise was slight with no
so pulling angle information was grouped into applications visible strap movement.
with any pulls >45° away from the limb (208, 40.6%) and those
with only pulls ≤45° from the limb (304, 59.4%). Applications After engaging the tightening system, in 37 applications, 22
with any pulls >45° were considered bad pull technique (Figure appliers returned to the strap/redirect system to do additional
2 pull technique). Pull technique was also assigned bad if the strap pulls or to disengage and completely redo strap pulls (9
redirect buckle or windlass rod was used as a holding location SOFTTW3, 7 TMT, 6 RST, 5 SOFTTW5, 3 X8T, 3 Tac RMT,
during pulling (redirect holding in 148, 28.9% of applications; 2 CAT, and 2 OMT). Both consume time, and pulls with an
rod holding in 42, 8.2% of 256 windlass rod applications). engaged tightening system are unlikely to gain strap tightness
beyond initial pulling.
Forty-two CAT7 and 38 OMT applications involved one ef-
fortful strap pull, and five CAT7 and nine OMT involved more Application Process Scoring: Tightening System
than two effortful strap pulls. The TMT had 25 applications Tightening-system understanding problems (Figure 2 under-
involving one effortful pull and 16 involving more than two standing) were uncommon for rotation-parallel-to-limb
effortful pulls (p=.0050 versus CAT7 and OMT). Self- securing windlass rods (5 CAT7 and 1 SOFTTW3 of 255 scorable),
strap/redirect-system applications involving one effortful strap rotation-perpendicular-to-limb ratcheting buckles (4 RST, 2
pull were 28 SOFTTW5, 22 X8T, 16 SOFTTW3, 13 Tac RMT, OMT, and 2 Tac RMT of 188 scoreable), and rotation- parallel-
and 13 RST; applications involving more than two effortful to-limb ratcheting dial (2 of 63 X8T, p=.53). One applier never
pulls were 28 Tac RMT, 25 RST, 25 SOFTTW3, 17 SOFTTW5, understood the tightening systems of the CAT7, SOFTTW3,
and 15 X8T. OMT, and RST but still managed to achieve occlusion with the
OMT and RST. Another applier had problems understanding
Optimal pull-related strap tightness (Figure 2 strap tightness the CAT7 and X8T tightening systems but achieved occlusion
and Figure 4) was not reached in 255 (50.6%) of 504 appli- with both. No other appliers had understanding problems
cations in which it could be scored. Applications with optimal with more than one tourniquet. Failure to ever understand the
pull-related strap tightness were more common with appliers windlass rod tightening system caused occlusion never to be
with any tourniquet experience (p=.0024 across all tourni- achieved in two CAT7 and one SOFTTW3 application. Fail-
quets, Figure 4). Applications with bad pull technique (Figure ure to ever understand the ratcheting-buckle tightening system
2 pull technique) reached pull-related optimal strap tightness did not prevent appliers achieving occlusion (one OMT and
less frequently than those with good technique (45.3% versus one RST).
54.4%; p=.049). Bad pull technique was most common with
the TMT and least common with the Tac RMT (p=.0002 for Some appliers with ratcheting-buckle understanding problems
differences across all tourniquets; Figure 2 pull technique). pulled on the ladder while holding the ratcheting buckle. Lad-
Among applications with bad pull technique, simple redirects der pulling alone was ineffective, but holding the ratcheting
had the highest number reaching optimal pull-related strap buckle during ladder pulling sometimes resulted in buckle

Tourniquet Processes | 19