Page 77 - JSOM Fall 2018

The Combat Application Tourniquet
Versus the Tactical Mechanical Tourniquet

Comparison of Performance in

Self-Application by Healthy Military Volunteers

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A. Beaven, MBChB, MRCS ; M. Ballard, FRCR ; E. Sellon, MBBS, MRCS, MSc(SEM), FRCR ;
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R. Briard, FRCR ; P.J. Parker, MB BCh, BAO, DipIMC, FRCSEd, FRCSOrth, FIMC 1

ABSTRACT
Background: Exsanguination from limb injury is an import­ Combat Application Tourniquet
ant battlefield consideration that is mitigated with the use of The C­A­T has saved many lives, particularly in the Ameri­
emergency tourniquets. The Combat Application Tourniquet can and British military campaigns. Studies have found that
(C­A­T ) is the current British military standard tourniquet. a single self­applied C­A­T may not always be sufficient to
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Methods: We tested the self­application of a newer tourniquet arrest bleeding when applied to the mid thigh. American and
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system, the Tactical Mechanical Tourniquet (TMT), against British military doctrine advocates the use of two C­A­Ts side
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self­application of the C­A­T. A total of 24 healthy British mil­ by side if bleeding is uncontrolled with one tourniquet. In
itary volunteers self­applied the C­A­T and the TMT to their fact, a real­world study reported the percentage failure of a
mid thigh in a randomized, sequential manner. Popliteal artery singly applied C­A­T to be 18%, with the thigh being the least
flow was monitored with a portable ultrasound machine, and successful body region. The C­A­T has benefitted from spiral
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time until arterial occlusion was measured. Pain scores were development: a continual improvement cycle refining model
also recorded. Results The volunteers allowed testing on their design in response to battlefield feedback. The seventh gener­
lower limbs (n = 48 legs). The C­A­T was applied success­ ation C­A­T has been manufactured and is being distributed
fully to 22 volunteers (92%), and the TMT was successfully for use. Improvements to the generation 6 model are intended
applied to 17 (71%). Median time to reach complete arterial to accommodate common user mistakes and include a single
occlusion was 37.5 (interquartile range [IQR], 27–52) seconds routing buckle, windlass rod of increased diameter, beveled
with the C­A­T, and 35 (IQR, 29–42) seconds with the TMT. windlass clip, reinforced strap, and beveled stabilization plate.
The 2.5­second difference in median times was not significant Manufacturer C­A­T Resources postulates that these improve­
(p = .589). The 1­in­10 difference in median pain score was ments increase application speed, simplify training, increase
also not significant (p = .656). The success or failure of self­ strength, and improve comfort. Initial manikin testing showed
application between the two tourniquet models as assessed by that the generation 7 outperformed the generation 6 in hem­
contingency table was not significant (p= .137). Conclusion: orrhage control, ease of use, and user preference. Figure 1
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The TMT is effective when self­applied at the mid thigh. It shows the C­A­T applied to the mid thigh.
does not offer an efficacy advantage over the C­A­T.
FIGURE 1 Combat Applied Tourniquet positioned at the mid thigh
Keywords: tourniquet; exsanguination; self-application; Com- but not fully tightened.
bat Applied Tourniquet; C-A-T; Tactical Mechanical Tourni-
quet; TMT

Introduction
Limb exsanguination and junctional hemorrhage remain im­
portant causes of preventable battlefield mortality. Limb tourni­
quets, therefore, are essential equipment during the Care Under
Fire and Tactical Field Care phases of care. The British Army
currently uses generation 6 of the Combat Application Tourni­
quet (C­A­T; C­A­T Resources, www.combattourniquet.com)
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for casualty care at point of wounding. Preclinical evidence is
clearly required when new styles of tourniquets become avail­
able in the marketplace, particularly if an established tourniquet
model is under consideration for potential revision or redesign.
*Correspondence to The Department of Orthopaedic Surgery, The Royal Centre for Defence Medicine, University Hospitals Birmingham Foun­
dation Trust, Mindelsohn Way, Edgbaston, Birmingham, B15 2WB, United Kingdom; or alastairbeaven@traumaresearch.uk
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1 Maj Beaven, LtCol Ballard, LtCol Briard, and Col Parker are at The Royal Centre for Defence Medicine, University Hospitals Birmingham
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Foundation Trust, Edgbaston, Birmingham, United Kingdom. LtCol Sellon is at The Royal Centre for Defence Medicine, University Hospitals
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Birmingham Foundation Trust, and Oxford University Hospitals National Health Service Foundation Trust, John Radcliffe Hospital, Headley
Way, Headington, Oxford, United Kingdom.
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