Page 38 - Journal of Special Operations Medicine - Winter 2014

worse than no tourniquet (increased bleeding, compart- applied directly on skin. This may not be of high im-
ment syndrome, hypovolemic shock, and death). 8 portance on a severely injured casualty; however, the
ratings may have relevance to training sessions. Train-
Venous occlusion without arterial occlusion has been ing session frequency may be diminished with more
reported in casualties presenting to a forward surgical pain-inducing designs. Additionally, recipient pain re-
team in Afghanistan. Despite tourniquets being applied sponses during practice sessions may inhibit users from
9
by special operations combat medics, flight medics, tightening tourniquets to arterial occlusion pressures in
combat medics, and general surgeons; 54 of 65 tour- practice sessions. This could adversely affect user per-
niqueted limbs had palpable pulses on arrival at the formance in the field.
forward surgical team. Fluid movements within the
9
casualties are an obvious reason for loss of arterial oc- Study Limitations
clusion between initial tourniquet application and pre- This laboratory study had several limitations. First, the
sentation at the next step of care. An additional reason RMT versus CAT comparisons were retrospective for
for arterial occlusion loss is changes in muscle tension. the CAT with a different set of recipients and appli-
Casualties may be tense during tourniquet application. ers. Second, the pressure measurement system does not
Muscles can only remain fully contracted for a limited provide tourniquet edge pressure gradient information,
amount of time prior to relaxing. The administration which could be especially relevant when looking at dif-
of pain medications might also result in muscle relax- ferent width tensioning systems for same width straps.
ation. Therefore, regardless of tourniquet design, ongo- Third, secured tourniquets were released after 1 minute
ing re-assessments of tourniqueted casualties are very precluding definitive answers regarding the shape of the
important. pressure loss curve beyond that time frame.

Ease of Use
With years of military use data, the CAT has a proven Conclusions
track record demonstrating that care providers can ap- This study had several important findings. First, the nar-
ply it. 6,9-12 Our results indicate that both the Tactical and rower ladder of the Tactical RMT did not result in any
the Mass Casualty Ratcheting Medical Tourniquet de- difference in pressure, achievement or maintenance of
signs are even easier to apply than the windlass Com- occlusion, ease of use, or discomfort ratings compared
bat Application Tourniquet in our laboratory. This may with the wider ladder Mass Casualty RMT. Second,
relate to the friction buckle designs. It may be easier to Ratcheting Medical Tourniquets with a wider ladder
pull a smooth, non–hook and loop strap through a fric- and larger buckle can have a concerning rate of tooth
tion buckle composed of two metal rings (RMTs) than skipping. Third, the equivalence of the overall strap
to pull a hook and loop covered strap through a friction widths led to the RMTs and CATs having pressure simi-
buckle composed of slotted plastic with gripping edges larities that included responses to time and muscle ten-
(CAT). The friction buckle and strap design differences sion changes. Fourth, the RMTs may have an advantage
did not result in different friction buckle pressures prior over the CAT in occlusion maintenance, but this will
to engagement of either tourniquet design’s tensioning require additional study.
system (ratchet or windlass).

Release of the RMTs requires lifting an interior portion Disclosures
of the ratcheting buckle to allow complete disengage- None of the authors have any financial relationships rel-
ment of the mechanism from the teeth of the ladder. evant to this article to disclose, and there was no outside
The space for a finger or thumb to engage the release funding. The study was performed at Drake University,
mechanism is larger on the larger buckle Mass Casualty Des Moines, Iowa.
designs, but this did not result in differences in ease of
release ratings. Thighs had higher Completion pressures
and more frequent non-Easy release ratings; this sug- References
gests that higher pressure applications make release 1. Eastridge BJ, Mabry RL, Seguin P, et al. Death on the bat-
more difficult. RMT release has a technique component tlefield (2001-2011): Implications for the future of com-
and a hand-strength component. The hand-strength bat casualty care. J Trauma Acute Care Surg. 2012;73:
component may well have contributed to having only S431–S437.
Easy release ratings from the male appliers. 2. Ochoa J, Fowler TJ, Gilliatt RW. Anatomical changes in
peripheral nerves compressed by a pneumatic tourniquet. J
Anat. 1972;113:433–455.
Discomfort 3. Dyck PJ, Lais AC, Giannini C, Engelstad JK. Structural al-
In the laboratory, the RMTs received lower discomfort terations of nerve during cuff compression. Proc Natl Acad
ratings than had the CAT with all tourniquets being Sci USA. 1990;87:9828–9832.

28 Journal of Special Operations Medicine Volume 14, Edition 4/Winter 2014