Page 48 - Journal of Special Operations Medicine - Winter 2015

Table 5 Tourniquet Recipient Discomfort*
Tourniquet Location Rating = None, No. Rating = Little, No. Rating = Moderate, No. Rating = Severe, No.
CAT Calf 2 6 5 3
SOFTT-W Calf 2 5 4 5
RMT-P Calf 6 6 4 0
SWATT Calf 2 10 3 1
CAT Forearm 7 7 1 1
SOFTT-W Forearm 4 5 7 0
RMT-P Forearm 10 4 2 0
SWATT Forearm 6 8 2 0
See Table 2 legend for expansion of abbreviations.
*p = .024 for combined calf and forearm differences in recipient discomfort between tourniquets.

assistance securing the SOFTT-W windlass. Although metal crosspiece that clamped down on the strap dur-
the windlass securing triangle of the SOFTT-W does ing strap pulling and thereby impaired pulling the strap
not allow as much backward travel of the windlass as tight enough to achieve desirable Friction Pressures. In
does the windlass securing clip of the CAT, SOFTT-W contrast, the slip-lock rings friction buckle design of the
Completion Pressures can still result that are lower than RMT-P allowed appliers to reach Friction Pressures as
Occlusion Pressures. high as or higher than those with the single routed CAT.

The assistance of a second person would probably allow
Discussion
higher Friction Pressures to be reached with the single
The CAT, SOFTT-W, RMT-P, and SWATT can all stop routed CAT and the RMT-P. Additionally, we believe
arterial flow when used on the calf or forearm. The working with appliers on a pulling-tight-around-the-
10.4cm-wide, elastic strap SWATT stops arterial flow limb technique rather than pulling outward from or
at the lowest pressures of the four tourniquets. Sur- tangential to the limb would probably also result in the
prisingly, the limb- and recipient-matched Occlusion achievement of higher Friction Pressures with the single
Pressure measurements with the three 3.8cm-wide, routed CAT and the RMT-P. Because of the nature of
nonelastic strap tourniquets varied significantly from the buckle design, we do not believe either intervention
each other. Not surprisingly, the smaller-circumference would be of substantial use for improving the SOFTT-W
forearms tended to have lower Occlusion Pressures Friction Pressures.
than the larger-circumference calves. Also, the pres-
sure change from Occlusion to Completion varies by Occlusion Pressure Detection
tourniquet-tightening system. Occlusion Pressures varied among the 3.8cm-wide tour-
niquets. This could represent actual differences in the
Friction Buckle Design and Friction Pressure pressures required to reach Occlusion among the three
Each of the 3.8cm-wide, nonelastic strap tourniquets 3.8cm-wide, nonelastic strap tourniquets. Alternately,
had a different friction buckle design. The CAT fric- this could represent difficulty detecting Occlusion as
tion buckle was single slit routed, rather than double early as it occurred with each tourniquet. The RMT-P
slit routed, and, therefore, was used predominantly for had the lowest Occlusion Pressures and the least scat-
strap direction change prior to strap securing with the ter in those pressures. Both windlass designs had higher
hook-and-loop. This routing is approved in the Tactical median Occlusion Pressure measurements with greater
Combat Casualty Care Guidelines as being effective, scatter than the RMT-P. The scatter with the windlass de-
13
faster, and commonly used even in leg CAT applica- signs started with minimums similar to the RMT-P and
tions. 12,16 Despite single slit routing, appliers frequently then was distributed to higher maximums (Figure 3).
did not reach Friction Pressures greater than 150mmHg,
and, consequently, more windlass turns than would be Differences in the tightening systems could account for
ideal were frequently necessary. 15,16 the greater and predominantly upward scatter of the
windlass tourniquets’ Occlusion Pressures than those
Unlike the CAT, the straps of the SOFTT-W and RMT-P with the RMT-P. The ratcheting system of the RMT-P
were composed of relatively smooth webbing. Both the results in self-securing, discrete increases in pressure. A
SOFTT-W and RMT-P had metal friction buckles, but pause occurs following each tooth advance. The pause
the buckle design of the SOFTT-W involved a moveable should allow the detection of Occlusion very close to

36 Journal of Special Operations Medicine Volume 15, Edition 4/Winter 2015