Page 39 - JSOM Winter 2017

Effects of Distance Between Paired Tourniquets

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Piper Wall, DVM, PhD *; Charisse Buising, PhD ; David Nelms, MD ;
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Lisa Grulke, BA ; Catherine Hackett Renner, PhD ; Sheryl Sahr, MD 6
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ABSTRACT
Background: In practice, the distance between paired tourni- the high pressure zone by adding a second tourniquet adjacent
quets varies with unknown effects. Methods: Ratcheting Med- to the first is recommended. In practice, the distance between
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ical Tourniquets were applied to both thighs of 15 subjects paired tourniquets varies. 3
distally (fixed location) and proximally (0, 2, 4, 8, 12cm gap
widths, randomized block). Applications were pair, single dis- The reported incidence of multiple tourniquet use on a single
tal, single appropriate proximal. Tightening ended one-ratchet limb varies and may be greater in military settings than civilian
tooth advance past Doppler-indicated occlusion. Pairs had settings (military: 193 of 638 limbs, 16 limbs of 90 casualties,
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alternating tightening starting distal. Results: Occlusion pres- 5 limbs of 70 casualties; civilian: 0 of 87 patients, 1 of 73
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sures were higher for: each single than respective individual patients, 4 of 105 patients ). In the King et al. work concern-
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pair tourniquet, each pair distal than respective pair proxi- ing limb tourniquets on casualty arrival at a Forward Surgical
mal, and each single distal than respective single proximal (all Team, the following statement indicates that some believe the
p < .0001). Despite thigh circumference increasing proximally, adjacency of multiple tourniquets matters: “These three tour-
occlusion pressures were lower with proximal tourniquet in- niquets were placed far apart from one another, making them
volvement (pair or single, p < .0001). Occlusion losses before act independently as single, narrow devices and not together
120seconds occurred most frequently with pairs (0cm 4, 2cm side-by-side as if one wide device; wider is more effective.” 3
4, 4cm 6, 8cm 7, 12cm 5 for 26 of 150), in increasing fre-
quency with increasingly proximal singles (0cm 0, 2cm 1, 4cm The study purpose was to determine the effects of increas-
1, 8cm 2, 12cm 6 for 10 of 150, p < .0001 for trend), and least ing intertourniquet distance on paired tourniquet pressures.
with single distal (2 of 150, p < .0001). Paired tourniquets re- The hypotheses were that increasing intertourniquet distances
quired fewer ratchet advances per tourniquet (pair distal 5 ± 1, would decrease the occlusion pressure benefit of paired tour-
pair proximal 4 ± 1, single distal 6 ± 1, single proximal 6 ± 1). niquets compared with a single tourniquet and would decrease
Final ratchet tooth advancement pressure increases (mmHg) intratourniquet pressure effects.
were greatest for singles (distal 61 ± 10, proximal 0cm 53 ± 7,
2cm 51 ± 9, 4cm 50 ± 7, 8cm 45 ± 7, 12cm 36 ± 7) and least Methods
in pairs (distal 41 ± 8, proximal 32 ± 7) with progressively less
pair interaction as distance increased (pressure change for the The Drake University Institutional Review Board approved
pair tourniquet not directly advanced: 0cm 13 ± 4, 2cm 10 ± 4, this prospective study involving the use of tourniquets on both
4cm 6 ± 3, 8cm 1 ± 2, 12cm –1 ± 2). Conclusions: Occlusion thighs of 15 healthy volunteers. Data collection took place Oc-
pressures are lower for paired than single tourniquets despite tober 2016 through November 2016. The tourniquets were
variable intertourniquet distances. Very proximal placement requested from and donated by m2 Inc.
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has a pressure advantage; however, pairs and very proximal
locations may be less likely to maintain occlusion. Increasingly Tourniquets
proximal placements also increase tissue at risk; therefore, dis- Tactical Ratcheting Medical Tourniquets (RMTs; November
tal placements and minimal intertourniquet distances should 10, 2015 manufacturing lot; m2 Inc., www.ratchetingbuckles
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still be recommended. .com) were used because their self-securing, ratchet-based
tightening system allows finer resolution pressure control than
Keywords: tourniquet; hemorrhage; first aid; emergency can be achieved with current commercially available windlass
treatment systems. The Tactical RMT consists of a 3.8cm-wide fabric
strap; a friction buckle composed of two overlapping, 4.0cm-
diameter metal rings with a rough, friction-enhancing coating
to secure the correctly routed strap around the limb; a 22.4cm-
Introduction
long, 1.9cm-wide thermoplastic polyamide linear rack with
Wider limb tourniquets generally require less pressure to 2.5 teeth/cm (ladder); and a 3.0cm-wide by 4.5cm-long ratch-
achieve arterial occlusion. Therefore, when bleeding cessation eting buckle with a 0.762cm-long slot to allow the cam action
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is not achieved with a single tourniquet, increasing the width of of the pawl when ratcheting.
*Address correspondence to piperwall@q.com
1 Dr Wall is a researcher in the Surgery Education Department of UnityPoint Health Iowa Methodist Medical Center, Des Moines, IA. Dr Buis-
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ing is a professor of biology and the director of the Biochemistry, Cell and Molecular Biology Program at Drake University, Des Moines, Iowa.
3 Dr Nelms is a surgery resident at UnityPoint Health Iowa Methodist Medical Center, Des Moines, IA. Ms Grulke is an emergency medical
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technician-paramedic and a laboratory instructor in the Biology Department of Drake University, Des Moines, IA. Dr Renner is the director of
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the Office of Research at UnityPoint Health Iowa Methodist Medical Center, Des Moines, IA. Dr Sahr is a trauma surgeon at UnityPoint Health
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Iowa Methodist Medical Center, Des Moines, IA.
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