Page 37 - JSOM Spring 2026

FIGURE 1 X8T-T2G tourniquet.
The X8T-T2G Tourniquet (X8T) has a
self-securing strap/redirect system with
a clip for clipping around the limb. The
self-securing system is composed of two
simple strap-redirecting buckles (boxes
present in two panels) with one end of the
strap sewn around the outer portion of
the primary redirect (white box), which
is the redirect with the clip; threaded
through the secondary redirect (blue box)
from outward towards the limb; then
passed between the limb surface and the
part of the strap permanently attached to
the primary redirect (white box); and then
threaded through the primary redirect
from inward away from the limb. The
red pull tab on the free end of the strap
precludes strap unthreading. The base
area between the two redirects contains a
self-securing tightening system composed
of a base with teeth covered with a dial
with teeth that allow unidirectional dial
rotation. The interlocking self-securing
teeth are visible when the base and dial
are separated (small panel in the lower
corner). Tourniquet strap shortening in
response to dial rotation occurs because a
strap secured around each redirect passes
through the top of the dial and is twisted
around itself with dial rotation. Ten teeth
advances (10 clicks) create 180° of dial
rotation (equivalent to one 180° wind-
lass-rod turn). Release of the applied X8T
requires sufficient separating of the dial
from the base to disengage the interlocked
teeth. Unclipping becomes possible when
the X8T is sufficiently loose.

tightening system with unidirectional dial rotation parallel to that would be counter to tourniquet application (e.g., current
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the limb surface (see Reference 3 for X8T video description). forearm or thigh injuries).
Dial rotation results in immediate, full-width circumferential
strap shortening via shortening of a strap that is sewn around Pressure Measurements
the secondary strap redirect and the clip of the primary strap Pressures were measured using a No. 1 neonatal-blood-
redirect. Ten teeth advances (10 clicks) create 180° of dial rota- pressure-cuff bladder inflated to 18mmHg above atmospheric
tion (equivalent to one 180° windlass-rod turn). pressure (baseline), secured beneath the limb-encircling strap
on the medial aspect of the limb, and connected to a Vernier
Appliers Pressure Sensor 400, Vernier LabPro interface, and Logger Pro
The research team was led by two researchers with extensive 3.16.2 Software (Vernier Science Education, Beaverton, OR,
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experience carrying out lab-based tourniquet studies that in- USA; www.vernier.com). Pressures were recorded every sec-
clude real-time pressure measurement and Doppler monitor- ond. The system was not used on arm circumferences <31.3cm.
ing. The other 13 researchers were undergraduate students
who were members of the Trauma Research Team for their Applications
first, second, or third year. All team members trained with all Application side was block randomized in sets of 10. X8Ts
of the equipment for a minimum of two months prior to col- were applied on mid-arm then same-side mid-thigh skin of
lecting the first study data. X8T application training and prac- seated recipients with the arm resting palm-up on a table and
tice involved arm and thigh applications on volunteering team the knee flexed approximately 90° with both feet resting on
members and included visible real-time pressure data, audible the floor or elevated surface. Distal arterial flow (radial artery,
real-time Doppler signal, and immediate verbal feedback re- dorsal pedal artery, or posterior tibial artery) was monitored
garding technique. with audible Doppler (Ultrasonic Doppler Flow Detector
Model 811 with 9.5MHz adult flat probe; Parks Medical Elec-
Following practice sessions with measurement of hands-off, tronics, Aloha, OR, USA; www.parksmed.com). Arterial oc-
pre-tightening-system-use pressure, eight researchers were cho- clusion was defined as loss of audible Doppler pulse. Arterial
sen as tourniquet appliers based on ability to frequently achieve flow return was defined as return of audible Doppler pulse.
X8T-pre-tightening-system-use pressures >100mmHg. Avail-
ability determined which applier did each application. After placement with the primary redirect buckle (redirect
with clip) positioned laterally for downward strap pulling, the
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Recipients applier pulled the strap as tight as possible and removed both
Volunteers were ≥18 years and had no known: bleeding or clot- hands from the tourniquet for pre-tightening-system-use pres-
ting abnormalities, circulation problems, pain syndromes, pe- sure (Figure 2). Tightening-system use began (dial rotation). To
ripheral neuropathies, connective tissue disorders, or conditions determine first arterial occlusion, a pause with hands off the

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