Page 41 - JSOM Spring 2026

FIGURE 4 Per click pressure increases. system when using it (both of which are problems we observed
with windlass-rod tightening systems in the concurrent study
with the shared set of recipients and shared appliers ). The
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self-securing X8T tightening system also has a significant time
advantage compared to non-self-securing windlass-rod sys-
tems when any additional tightenings are required (an IQR
of two to three seconds from pulse detection to completion
of additional tightening versus IQRs from 9 to 21 seconds for
the windlass-rod tourniquets in the concurrent study with the
same appliers ).
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We did not rate or score difficulty releasing the X8T tighten-
ing system. It was sometimes very difficult. Difficulty creating
releasing separation between the teeth of the dial and the teeth
of the base related to the completion pressure, the location of
the handle parts of the dial in relationship with the corners of
the base, and possibly the number of clicks. We believe increas-
ing the size of the base corner areas on which one pushes down
and perhaps also slightly increasing the length of the handles
of the dial would make intentional releasing easier.

When we released the X8T tightening system, we did not try to
release it one click at a time. We consider it difficult to limit the
initial tension releasing to only one click’s worth of releasing
Each X8T application is shown with a circle; the whiskers extend rotation. After the initial tension releasing, releasing the rota-
from minimum to maximum; the boxes extend from 25th percentile to tion of the X8T tightening system one click at a time becomes
75th percentile (bound the IQR); and the medians are inside the boxes. easy. It is possible that making releasing easier might also im-
Data for arm applications are green, for thigh are blue. Arm data from prove intentional control over the initial unwinding of the dial.
subjects requiring additional clicks after 1st completion are connected
by dashed lines and have the same color coding as in Figure 3 (n=19, Control over the speed of resumption of arterial flow may be
21 arms were too small for pressure measuring including two that advantageous during tourniquet removal for conversion or
required additional clicks). Thigh data from three subjects requiring definitive care. However, the presumption that windlass-rod-
more than one additional click after 1st completion are connected by related potential control over the speed of resumption of arte-
dashed lines and have the same color coding as in Figure 3 (n=40). The rial flow is advantageous seems tenuous considering data from
arm dashed line data points are from different subjects than the thigh
dashed line data points. One arm application with occlusion before collapsible tube flow studies showing the non-linear relation-
tightening-system use was excluded from per click pressure increase to ship between luminal surface area and flow 11,12 and consider-
1st completion. Per click additional pressure increases occurring after ing the rapidity of resumption of full Doppler pulse volume
1st completion were greater than per click 1st completion pressure in the lab when intentionally striving for slow resumption of
increases (P<.0001).
arterial flow with windlass-rod-based-tightening systems (data
not shown).
Because of the full-width and finer pressure-increment tight-
ening system of the X8T, the first and any subsequent thigh The base area of the X8T has heat-melted webbing ends.
completion pressures were predominantly lower than noted During X8T application practice, we found the corners of the
with the shared set of recipients in the concurrent study us- melted webbing uncomfortable for no functional gain, so we
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ing windlass-rod-tightening-system tourniquets. Even though opted to tape over the corners. Anyone practicing with this
only larger arms had X8T pressure monitoring, the X8T arm- design directly on skin would probably appreciate either taped
completion pressures were also predominantly lower than corners or alteration of the webbing melting process such that
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noted with the windlass-rod-tightening-system tourniquets. the corners do not feel sharp when the tourniquet is applied at
Completion pressures are what matter regarding pressure- an arterially occlusive pressure.
related injury to underlying structures. The pressure increase
per discrete advancement of the tightening-system increases Limitations
in magnitude as the tourniquet pressure increases and is also Laboratory-setting limitations included ideal application posi-
greater with arm applications than thigh applications. Also, tions; calm, uninjured recipients; substitution of audible Dop-
arms have less tissue volume protecting major nerves. These pler for bleeding; good lighting; limited distractions; and a
factors all indicate the potential clinical importance of being small group of calm, trained appliers. Recipients were a conve-
able to use lower completion pressures, especially when the nience sample recruited from friends, college students including
time from tourniquet application to tourniquet conversion or male and female collegiate athletes, and college faculty. A major
to definitive care may be long. limitation regarding tourniquet wear is that applications were
only as tight as needed for completion one click after audible
The self-securing strap/redirect system and self-securing tight- pulse loss or return. Use under fire would be likely to involve
ening system of the X8T remove the potential for user failure worse application positions and therefore lower pre-tightening
to properly secure the strap/redirect system or the tightening system pressures and more dial-rotation clicks and potentially
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system. The self-securing nature of the X8T tightening sys- tightening-system use to “as tight as possible.” “As tight as pos-
1
tem also removes potential struggles to secure the tightening sible” is quite different from “as tight as needed” in a labora-
system and the potential to accidentally release the tightening tory and would involve more dial-rotation clicks.
X8T Tourniquet | 39