Page 14 - JSOM Spring 2024

the average pressure applied by the entire TPT2. This offers 67cm long and is wrapped around the limb starting with the
the ability to determine total tourniquet average arterially oc- outward facing hook-and-loop end. The outward hook-and-
clusive pressures with TPT2 applications, which is data that loop is eventually engaged by inward facing hook-and-loop
can be used to help develop an emergency-use limb tourni- on the remaining 15.5cm-long portion of the inner strap (no
quet certification system. Collecting TPT2 arterially occlusive bladder). At the bladder-to-no-bladder junction of the inner
pressures data for certification system development use has the strap, the hook-and-loop covered outer strap begins. The
beneficial side effect of providing clinically important infor- 94.0cm-long outer strap is wrapped around the inner strap in
mation concerning how much pressure a TPT2 is likely to be the direction opposite to the direction of wrapping the inner
exerting on a limb to achieve arterial occlusion. strap around the limb. The hook-and-loop covered outer strap
is secured by placing the triglide that is on the outer strap into
The study purpose was to collect TPT2 pressures required the receiving clip present at the junction of the inner and outer
for arterial occlusion when placed on adult distal forearms straps, pulling the outer strap through the triglide to remove
and mid-thighs. The two anatomic locations were chosen be- slack from the wrap around the inner strap, and then wrap-
cause the current ASTM International tourniquet certification ping the redirected outer strap back onto itself for hook-and-
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process is expected to involve tourniquet applications to a loop to hook-and-loop adherence. The TPT2 is then inflated
15.6-cm circumference, cylindrical device and a 70.5-cm cir- using a hand bulb attached to a tube that connects to the blad-
cumference, cylindrical device. The hypotheses were that sig- der near the junction of the inner and outer straps. We modi-
nificantly less pressure would be required on forearms (smaller fied the TPT2 by replacing the hand bulb with two stopcocks,
circumference) and that mid-thigh occlusion pressures would a syringe for varying volume, and a Vernier Pressure Sensor
be similar to those reported for 3.8cm-wide emergency-use 400 (Vernier Software and Technology, www.vernier.com) for
limb tourniquets when using a small, inflated bladder under a continuous pressure monitoring.
portion of the tourniquet. 3–10
Tourniquet Subjects
Seventy volunteers met inclusion criteria: age ≥18 years; no
Methods
known bleeding or clotting abnormalities, circulation prob-
The Drake University Institutional Review Board approved lems, pain syndromes, peripheral neuropathies, connective tis-
this prospective study, which took place August 2022 through sue disorders; and no known conditions that would be counter
December 2022. The TPT2 (MFG Nov 21, Lot 58845) was to tourniquet application (e.g., current forearm or thigh
donated by Alphapointe for use developing devices for non- injuries).
pneumatic emergency-use limb tourniquet certification.
Pressure Measurements
Tourniquet Pressures were measured using a Vernier Pressure Sensor
The TPT2 is 5.1cm wide when deflated (Figure 1). The part 400, Vernier LabPro interface, and Logger Pro 3.16.2 Soft-
of the TPT2 containing the 63.5cm-long inflatable bladder is ware (Vernier Software and Technology, www.vernier.com).

FIGURE 1 Tactical Pneumatic Tourniquet 2" (TPT2).

(A)
(B)

(D)

(C)
5.1cm-wide TPT2 connected to dual stopcocks, air-filled syringe, and pressure sensor. The coyote tan inner part of the shown coil contains the
bladder. The triglide strap redirect buckle is placed in the clip at the junction of the end of the bladder-containing portion with the clip and with
the 15.5-cm bladderless extension of the inner strap and with the 94.0-cm black outer strap. (A) TPT2 loosely wrapped. (B) TPT2 wrapped as it
would be when applied to a wrist. (C) TPT2 being inflated on thigh with 100% side-to-side overlap of wraps of inner and outer straps. (D) TPT2
being inflated on forearm with 100% side-to-side overlap of multiple wraps of inner strap and wrap of outer strap.

12 | JSOM Volume 23, Edition 1 / Spring 2024