Page 22 - JSOM Fall 2025

likely to progress to a clip sufficiently open to not function. Special Operations Forces Tactical Tourniquet Generation 3
However, the unintentional increasing of clip opening sug- (SOFTTW3; TacMed Solutions , Anderson, SC. 348, 317-
™
gests compressive force might easily close the clip opening to a 384mmHg). We believe this results from the CAT’s not-
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non-functioning degree. full-limb-encircling-strap-width-tightening design (only the
2.54cm-wide inner band actually tightens). Having similar
Quality Control/Design Consistency tightening designs, we expected and found the SICH, DNIPRO,
With only four of each Ukrainian-manufactured tourniquet, and PULS to have higher thigh occlusion pressures than the X8T
we did not see any DNIPRO or PULS tourniquet-to-tourniquet on the same recipients (medians of 423, 426, and 398mmHg
differences. There were SICH differences in opening width be- versus 359mmHg, Figure 3B). Surprisingly, the Y&B occlusion
tween the two inward prongs of the modified triangle, which pressures (median 402mmHg) were also higher than the X8T’s;
slightly impacted ease of rod securing. There were SICH differ- perhaps this relates to the attachment of the Y&B’s limb-
ences in the length of fabric securing the modified triangle to the encircling strap being less than full width and possibly creating
base area, which had no functional impact. There were Y&B centralized pressure.
differences in length, edge-to-edge location, and number of
stitching passes creating the strap loop around the windlass rod. The occlusion-pressure differences between windlass-rod-
tightened tourniquets and tourniquets with finer-resolution
General Design Considerations tightening systems may be clinically unexciting. However, this
All the tourniquets were long enough to apply on the study shows once again 13,20 that tourniquets using tightening
75.5cm-circumference, largest recipient thigh (lengths: SICH systems involving 180° windlass-rod rotations frequently have
96.6cm, DNIPRO 93.5cm, PULS 94.0cm, Y&B 109.2cm). The completion pressures hundreds of mmHg higher than neces-
SICH, DNIPRO, and PULS were not long enough to use the sary and much higher than 500mmHg, even when applications
base-area strap-securing features in 13, 14, and 8 recipients, are restricted to only as tight as necessary for completion with
respectively. As noted in Table 2, only the Y&B had applica- occlusion. Considering the respective occlusion pressures and
tions that physically could not be secured. Table 4 lists design tissue volumes protecting major nerves, the number of arm ap-
thoughts for Ukrainian-manufactured tourniquets. plications with completion pressures greater than 500mmHg
is even more concerning for windlass-rod tourniquets than
is the number of thigh applications. Non-arterially occlusive
Discussion
tourniquets are life- and limb-threatening, 1,21 but tourniquet-
The key finding was the SICH, DNIPRO, and PULS always pressure-related nerve injuries are also undesirable and relate
achieved completable occlusion, but the Y&B did not. Addi- to both the duration and magnitude of pressure. The classic
tionally, the Y&B had a slider redirect buckle that, when un- study to reference for 500mmHg and higher being undesirable
threaded, readily separated into two pieces for easy loss of the involved a maximum duration of only three hours. Com-
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slider and also offered multiple incorrect rethreading options; bat-related tourniquet times in the Russo-Ukrainian War often
a windlass rod that could be removed from the strap; and exceed three hours, 23–25 and in the United States military, some-
inadequate mobility of the rod-securing triangle preventing times exceed three hours. 1,26
always being able to secure the windlass-rod.
Resolution of tightening-system-pressure increases becomes
Achievement and maintenance of arterial occlusion until in- increasingly important as tourniquet pressure increases. The
tentional release (for time or pressure) occurred with every magnitude of pressure increase per 180° turn is not linear. In-
SICH, DNIPRO, and PULS application and every arm Y&B stead, the increase per turn is greater when the turn starts from
application. Y&B problems occurred during thigh applications. a higher pressure (note the Figure 3D greater increases per turn
Turn-related rod migration too close to the triangle caused two for turns occurring after first completion and the association
instances of confirmed physical preclusion of rod securing. of lower Y&B pre-tightening pressures in Figures 3A and B
Turn-related rod migration also caused two instances of ap- with lower Y&B first-completion pressure increases per turn in
plier struggling with and not securing the rod that were not Figure 3D). A possible trade-off for the poor tightening resolu-
confirmed to be from physical preclusion before hold on the tion of windlass-rod tightening systems is the potential to slowly
rod was lost or application was released for time. The Y&B decrease tourniquet pressure during removal for conversion or
slider-redirect-associated-strap-pulling friction promoted lower definitive care. Flow data from collapsed-tubes studies suggests
pre-tightening-system pressures (Figure 3A, 3B), which trans- the extent of this possible benefit regarding how quickly how
lates to more windlass-rod turns with accompanying rod mi- much blood flow hits any developed clots is questionable. 27,28
gration (≥3 rod turns in three of 30 arm and 24 of 30 thigh
applications, Figure 3C). Rod-turn data from United States- Regarding wear, the visible Y&B stitching failures did not
military-combat-related applications of Combat Application occur with one use but would clearly be concerning in situ-
Tourniquets (CAT, CAT Resources, Rock Hill, SC) shows 79% ations involving tourniquet reuses. If the other Y&B major
®
of applications involved ≥3 rod turns, despite 37% of appli- design problems were addressed, the stitching should also be
cations using the relatively low-friction simple-redirect-buckle strengthened. Any tourniquet reuse situations should involve
strap routing. Therefore, we expect the Y&B failure incidence tourniquet visual examinations, complete resetting including
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on thighs would increase in non-ideal settings. full untwisting of all straps and checking for base-plate migra-
tion (happens with CAT but did not with DNIPRO or PULS),
14
Research with different recipients shows the 3.8cm-wide CAT and consideration of reuse risk-to-benefit ratios.
requires higher pressures to reach thigh arterial occlusion
(median 424, IQR 375-485mmHg) than does the 3.8cm-wide As noted in Table 4, all four Ukrainian-manufactured tourni-
Tactical Ratcheting Medical Tourniquet (Tac RMT; m2inc., quets had designs that avoided creating recipient pain for no
Colchester, VT. 338, 356-415mmHg) or the 3.8cm-wide functional gain. This should be the case for all tourniquets.

20 | JSOM Volume 25, Edition 3 / Fall 2025