Page 55 - JSOM Fall 2019

tourniquet application–related issues. We also viewed tourni- the 2003 paper by Lakstein et al. Correct application of the
48
quet-related videos linked to the Stop the Bleed website (www SWATT involves a relatively unstretched starter wrap around
.bleedingcontrol.org) and a sampling of videos found using the the limb, followed by wraps stretched to 200% of the original
search term “stop the bleed video” in Google, and we looked material length with the end secured by tucking under a previ-
at Tactical Combat Casualty Care training slides and manu- ous wrap (user preplanning is essential).
facturer instructions for the C-A-T, the most common tourni-
quet in the papers, pictures, and videos. Optimal Application Surface
For all conditions other than Care Under Fire, tourniquets
should be applied directly on skin rather than over clothing.
1
Results
The importance of application directly on skin is indicated by
Types of Tourniquets in References the following three statements from a publication regarding
C-A-Ts are composed of a 3.8cm-wide, hook-and-loop– 428 tourniquets used on 309 limbs of 232 patients in a mili-
covered nonelastic strap; a non–self-securing redirect buckle; tary setting: (1) “Padding (such as the patient’s clothes) under
6
and a non–self-securing windlass mechanical advantage tight- the tourniquet was associated with tourniquet looseness.” (2)
ening system. Generation 7 C-A-Ts, released in 2016, have a “Loosening was increased by keeping clothing under tourni-
simple redirect buckle that only allows strap single-routing. quets and by transportation.” (3) “Materials under a tour-
Generation 6 C-A-Ts have a triglide redirect buckle through niquet should be removed at the first opportunity to avoid
which the strap could be double-routed (triglide use) or sin- looseness.” Reports concerning civilian medical care tour-
6
gle-routed (simple redirect). For both generations, users must niquet use 17,49–55 indicate tourniquet applications in civilian
secure the hook-and-loop strap to itself and one end of the settings are generally not Care Under Fire; therefore, civilian
windlass rod of the mechanical advantage tightening system tourniquet training should involve application on skin as part
by placement within a plastic bracket. of optimal technique.

The other two families of nonelastic-strap tourniquets present Optimal Direction of Pull
in the publications were Special Operations Forces Tactical For tourniquet designs with a redirect buckle, the optimal di-
®
Tourniquets-Wide (SOFTTW; Tactical Medical Solutions, rection of force application during the process of pulling the
®
www.tacmedsolutions.com) and Ratcheting Medical Tour- strap tight is 180° from the direction of the strap as it encoun-
niquets (RMT; m2 Inc., www.ratchetingbuckles.com). Both ters the buckle. In other words, the strap should be pulled
56
®
have self-securing redirect buckles and smooth straps (no tangential to the limb surface at the location of the redirect
hook-and-loop). SOFTTWs have 3.8cm-wide straps and a buckle (a pulling angle of 0°); the strap should not be pulled at
non–self-securing windlass mechanical advantage tightening an angle outward from the limb at the redirect buckle. If the
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system. RMTs have a self-securing ratcheting buckle mechani- buckle is stationary, the equation detailing the effect of pulling
cal advantage tightening system. angle is as follows: Tourniquet tightening force on the redirect
buckle = square root of (2 × (pulling force) × cos(pulling an-
2
Generation 3 SOFTTWs have a self-securing slider redirect gle) + (2 × pulling force) ). This means a strap-pulling angle
2
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buckle with a U-shaped sliding piece and metal round stock directly away from the limb (90°) results in a strap-tightening
as the outer part of the buckle. The outer part of Generation force on the redirect buckle that is only 70% of what would
2 SOFTTW slider redirect buckles is metal flat bar. Both gen- have been achieved with a strap-pulling angle tangential to the
erations have a quick-connect system to allow strap passage limb (0°).
around a limb with the buckle threaded and are challenging
to pull tight. For both generations, users must secure one end Establishing Optimal C-A-T Application Technique
of the windlass rod of the mechanical advantage tightening From October 2011 through spring 2015, five publications
system by placement within a small plastic triangle. established optimal C-A-T application technique as involv-
ing the following: strap single-routing through the buckle, 58,59
RMTs in the publications were the 3.8cm-wide Pediatric, achieving sufficient strap tightness to require only one wind-
3.8cm-wide Tactical, and 5.1cm-wide Wide. All have self- lass 180° turn from a starting windlass rod position parallel to
securing redirect buckles composed of two overlapping, rect- the strap to reach arterial occlusion (strap applied pressure
8,9
angular, metal round stock rings with rough coating. All have of at least 150mmHg before windlass engagement ), and ro-
60
a self-securing ratcheting buckle that advances along a toothed tating the windlass rod with the slot in the rod maintained
plastic ladder as the mechanical advantage tightening system. parallel to the stabilization plate, which becomes increasingly
7
difficult with increasing windlass turns.
Noncommercial and commercial types of elastic tourniquets
were mentioned in the publications. Both use tourniquet- The October 2011 publication detailed C-A-T damage occur-
7
material elastic recoil as the mechanical advantage tightening ring when strap slack was present before windlass use and,
system, and neither involves a redirect buckle. The noncom- in Figure 2 of the publication, also shows the error of not
mercial elastic tourniquet was latex surgical tubing wrapped maintaining the C-A-T windlass slot parallel to the stabiliza-
tightly at least twice around the injured limb and secured with tion plate when turning because of failure to achieve adequate
a surgical hemostat. The commercial elastic tourniquets were strap tightness before using the windlass. Based on the occur-
17
the Israeli Defense Forces (IDF) tourniquet and the Stretch rence of C-A-T damage, the authors called greater than three
Wrap And Tuck Tourniquet (SWATT; H & H Medical Corp., turns “too many twists of the windlass.” 7
www.swattourniquet.com).
In 2013, two laboratory studies using the C-A-T on a HapMed
™
At 10.4cm-wide by 150cm-long, the SWATT is wider and thigh model (CHI Systems, Inc., www.hapmedtraining.com)
shorter than the 6.5cm-wide by 200cm-long IDF tourniquet of were published. 9,58 One evaluated the security of single-routing

Getting Tourniquets Right | 53