Page 34 - JSOM Fall 2021

FIGURE 3 Arm tourniquet applications.

(A) (B)

The white tubing and stopcock are part of the pressure-measuring system. The holding loop of the commercially available Tactical Ratcheting
Medical Tourniquet (Tac RMT, NEAR) is tan on the outside and black on the inside. The holding loop of the modified Tac RMT (FAR) is red.
Self-applications to the arm involved holding the arm against the body to prevent tourniquet rotation around the limb and did not involve biting
the holding loop. (A) Self- and buddy-applications of the standard, commercially available Tac RMT with the holding loop near the strap redirect
buckle (NEAR). Buddy-applications of the NEAR version involved applying force to the holding loop with the left hand and pulling the free end
of the strap with the right hand with no crossing of the hands or of parts of the tourniquet. (B) Self- and buddy-applications of the modified Tac
RMT with the holding loop placed at the other end of the toothed ladder from the strap redirect buckle (FAR). Buddy-applications of the FAR
version involved applying force to the holding loop with the fingers of the left hand while the left thumb assisted the strap into the redirect buckle
and the right hand pulled the free end of the strap. To achieve this, the hands were crossed for the initial grasping of the respective parts of the
tourniquet. In the photograph, the strap-assisting thumb of the left hand is partially obscured by the overlying strap.

Mid-thigh applications included self- and buddy-applications, by any use of the holding loop (Figure 3). For paired buddy-
with each tourniquet oriented so that the strap was pulled applications to the arm, the FAR holding location allowed for
downward through the laterally located strap redirect buckle a crossed-hands technique that could incorporate thumb use
(Figure 4A and 4C) and self- and buddy-applications oriented to feed the strap into the redirect buckle (Figure 3). Arm hands
so that the strap was pulled upward through the laterally lo- off, secured pressures are shown in Figure 5A and 5B.
cated redirect buckle (Figure 4B and 4D). All mid-thigh appli-
cations used the holding loop. For self- and buddy-applications to the thigh (Figure 4), the
FAR holding location allowed for incorporation of thumb use
The applications only involved pulling the strap as tight as to feed the strap into the redirect buckle when the tourniquet
possible. The ratcheting tightening system was not used, and orientation was such that the pull through the redirect buckle
no Doppler monitoring of the pulse was involved because was upward. Thigh hands off, secured pressures are shown in
complete tourniquet application with arterial occlusion was Figure 5C and 5D.
not a part of this small proof-of-concept study.
Among the six pairs of arm and thigh applications that used
Pressure Measurements both hands and did not incorporate thumb feeding of the strap
Pressures were measured using a No. 1 neonatal blood pressure into the redirect buckle as part of the FAR holding location
cuff (2.2 × 6.5 cm bladder, single tube) at 18 mmHg above at- applications, five pairs had higher secured pressures with the
mospheric pressure (baseline) secured beneath the tourniquet NEAR holding location (Figure 5C). Among the five pairs of
6
strap with the bladder medially located, just past the far end applications that used both hands and used thumb feeding of
of the toothed ladder from the redirect buckle. The bladder the strap into the redirect buckle as part of the FAR holding
was connected to a gas pressure sensor, LabPro interface, and location applications, four pairs had higher secured pressures
Logger Pro Software (Vernier Software and Technology; www with the FAR holding location (Figure 5B and 5D).
vernier.com). Pressures were recorded every tenth of a second.
Discussion
Results
The key findings are that suggestive results found with ap-
The arm and thigh circumferences were 32 and 33 cm (arms) plications in model setups did not translate to higher strap
3,4
and 52 and 48 cm (thighs). The direction of strap pulling at pressures with the standard strap-pulling technique during ei-
the redirect buckle was attempted to be maintained parallel to ther self- or buddy-applications to thighs or arms. The FAR
the incoming strap. The type of pull, holding location, and holding location resulted in clearly improved secured pressures
5
secured pressures are shown in Figures 3 through 5. only when the thumb of the holding-location hand actively
assisted the strap feed into the redirect buckle. This is not a
For paired self-applications to the arm, tourniquet sliding was simple or obvious strap-pulling technique and requires specific
prevented by holding the arm against the body, rather than redirect buckle and hands orientations to be applicable.

32 | JSOM Volume 21, Edition 3 / Fall 2021