Page 53 - Journal of Special Operations Medicine - Spring 2015

reported with standard deviations. Statistical signifi­ 100 times prior to this study and had some visible fabric
cance was set at p ≤ .05. All p values <.10 are reported. wear at both rivets prior to use in this study. It was used
on the fifth through the 10th recipients (41.5–59.4cm
thigh circumferences). The strap did not back slide dur­
Results
ing any use of Tactical RMT A. During the fifth appli­
Tourniquets were applied to seven women and five men. cation (125mmHg target Friction Pressure with only the
Recipients ranged in age from 20 to 54 years (median: 75mmHg target remaining) to the ninth recipient (54.5cm­
28 years), had systolic blood pressures from 96 to 130 circumference thigh), the two metal rings of the friction
mmHg (median: 118mmHg), and had thigh circumfer­ buckle moved sideways with sideways gathering of the
ences from 41.5 to 62cm (median: 54.5cm). fabric holding them and sideways gathering of the strap
within them, creating difficulty reaching the 125mmHg
CAT Issues Encountered target Friction Pressure. The problem recurred during
Some of the issues encountered with the CATs have previ­ the fourth application (75mmHg target Friction Pressure
6,7
ously been reported. Lower Friction Pressures were asso­ with 125 and 50mmHg targets remaining) to the 10th
ciated with tearing of the fabric welds indicated in Figure 1 recipient (48.5cm­circumference thigh). On the first ap­
(mild deformation ) and increased windlass turns required plication (125mmHg target Friction Pressure) to the 11th
9
to reach Occlusion. Increased windlass turns were associ­ recipient (62cm­circumference thigh and highest Occlu­
ated with difficulty twisting the windlass. There was one sion Pressures), the problem recurred and was intractable
occurrence (62.0cm­circumference thigh) of inability to to attempts to prevent the rings’ sideways sliding. The
turn the windlass to the Completion secure point (which fabric wear at the rivet near the friction buckle was felt
would have been four turns). Increased windlass turns to allow the problem, and the application on the 11th re­
were also associated with increased twisting of the inner cipient was therefore restarted using the Tactical RMT C.
strap within the slot of the windlass. The inner strap
was untwisted and smoothed between each application. The Tactical RMT C was the third Tactical RMT used
The issue encountered with the CAT, which was not in this study. It was received from the manufacturer
noticed in other reports, was slipping of the hook­and­ in response to our report of the back sliding problem
loop covered 3.8cm­wide strap farther onto the base. with the Tactical RMT B. Tactical RMT C was already
This resulted in a reduced distance between the friction their production model because of their concerns that
buckle­attached fabric sleeve from which the inner strap the noncoated buckle might allow the strap back slid­
originated and the hook­and­loop covered strap into ing that we reported. The polyethylene insert was also
which the inner strap goes. This slipping of the hook­ already in this model because of their concerns that the
and­loop covered 3.8cm strap interfered with turning friction buckle metal rings might be able to be pulled
the windlass. Each time slippage occurred, the hook­ sideways, especially with the repeated uses of practice
and­loop covered strap was repositioned to the original tourniquets. Tactical RMT C was used on the 11th and
starting position before the next application. 12th recipients (62cm and 54cm thigh circumferences,
respectively). No strap back sliding in the friction buckle
Tactical RMT Issues Encountered and no rings sliding sideways occurred during the 12 ap­
The Tactical RMT B was the first Tactical RMT used in plications of the Tactical RMT C.
this study. It had been used in the laboratory fewer than
50 times prior to this study. It was used on the first 4 re­ A failure of the pawl to correctly advance along the
cipients (48.2–61.5cm thigh circumferences). During the ladder occurred during one application of the Tacti­
100mmHg Friction Pressure target application on the cal RMT B but did not preclude reaching Occlusion
second recipient (61.5cm­circumference thigh), the strap (61.5cm­circumference thigh). The same problem also
back slid in the friction buckle during the ratchet­based occurred during four applications (62cm­circumference
tightening, but Occlusion was still reached. During the thigh) with the Tactical RMT C. In each instance, the
first and second application of this RMT on the fifth failure of the pawl to correctly advance along the ladder
recipient (56.5cm­circumference thigh), the strap clearly was stopped by putting pressure on the pawl toward
back slid during ratchet­based tightening and did so on the ladder during ratcheting buckle hinging and did not
every tooth advance on the second application such that preclude reaching Occlusion.
reaching Occlusion was not possible. RMT applications
on the fifth recipient were therefore restarted using the Releasing the ratcheting buckle of the Tactical RMTs
Tactical RMT A, and the manufacturer was contacted was not physically easy. The release mechanism in­
regarding the problem. volves lifting the indicated end of the internal part of
the ratcheting buckle to release the internal pawl. Some
The Tactical RMT A was the second Tactical RMT used finger/thumb strength was required to operate the re­
in this study. It had been used in the laboratory well over lease mechanism. We think that more digit strength was

Initial Tourniquet Pressure Does Not Affect Arterial Occlusion Pressure 43