Page 52 - Journal of Special Operations Medicine - Summer 2015

Role of the Windlass in Improvised Tourniquet Use
on a Manikin Hemorrhage Model

Matthew P. Altamirano; John F. Kragh Jr, MD;
James K. Aden 3rd, PhD; Michael A. Dubick, PhD

ABSTRACT

2,3
Background: In emergencies when commercially de- were at risk of death by wound exsanguination. No
signed tourniquets are unavailable, hemorrhage may longer bystanders, these responders gave first aid by
need to be controlled with improvised tourniquets. In wrapping and tightening a shirt around a limb, and these
the aftermath of the Boston Marathon bombing, no im- makeshift tourniquets reportedly helped save lives. Such
4
provised strap-and-windlass tourniquets were used to field tourniquets were replaced at the hospitals with
treat casualties; tourniquets without windlasses were dressings, commercial tourniquets, or blood pressure
2,3
used. The purpose of the present study is to determine cuffs ; observers noted that tourniquets improvised by
the effectiveness of improvised tourniquets with and first responders were ineffective, as hemorrhage was not
without a windlass to better understand the role of the controlled. The lifesaving–ineffective contradiction in-
1,2
windlass in tightening the tourniquet strap. Methods: An dicates confusion and a need to better understand impro-
experiment was designed to test the effectiveness of im- vised tourniquets. The confusion and contradiction exist
provised strap-and-windlass tourniquets fashioned out fundamentally because there is essentially no substantial
of a tee shirt on a manikin thigh. Two users conducted research into the optimal use of improvised tourniquets.
40 tests each with and without the use of a windlass. Re- This lack of research leaves knowledge gaps unfilled re-
sults: Without a windlass, improvised tourniquets failed garding best tourniquet practices.
to stop bleeding in 99% of tests (79 of 80 tests). With a
windlass, improvised tourniquets failed to stop bleeding A strap-and-windlass design is an ancient way to use a
in 32% of tests (p < .0001). In tests with no windlass, at- rod to wind a strap more tightly around a limb; a key
tempts to stop the pulse completely failed (100%, 80 of step in improvising tourniquets is to twist a strap with
80 tests). With a windlass, however, attempts to stop the a windlass to gain mechanical advantage in tightening.
pulse failed 31% of the time (25 of 80 tests); the differ- However, to our knowledge, no one in Boston reported
ence in proportions was significant (p < .0001). Conclu- windlass use with an improvised tourniquet. If the role
sions: Improvised strap-and-windlass tourniquets were of the windlass was made clear, then tourniquet prac-
more effective than those with no windlass, as a wind- tice might be improved. A theory is that an inadequately
lass allowed the user to gain mechanical advantage. tightened strap can occlude limb veins but not arteries;
However, improvised strap-and-windlass tourniquets venous tourniquets control venous bleeding while arte-
failed to control hemorrhage in 32% of tests. rial tourniquets control both venous and arterial bleed-
ing. If so, then a venous tourniquet may be effective only
5
Keywords: first aid; hemorrhage; tourniquets; shock; dam- for venous bleeding and not for arterial bleeding. Fur-
age control; tourniquet, makeshift; tourniquet, homemade; thermore, such effectiveness for venous hemorrhage may
strap-and-windlass be only brief since paradoxical bleeding may soon occur. 5

The purpose of the present study is to determine the ef-
fectiveness of improvised tourniquets with and without
Introduction
a windlass to better understand the role of the windlass
Explosions on Boylston Street near the crowded finish in gaining mechanical advantage in tightening the tour-
line of the 2013 Boston Marathon caused more than niquet strap.
260 casualties, which, in turn, spurred nearby people
to improvise tourniquets to stop limb bleeding. These Methods
1,2
first people to respond made tourniquets fashioned out
of clothing such as shirts from nearby runners or from This study was conducted under a protocol reviewed
blast-damaged storefronts, for use on casualties who and approved by the Regulatory Compliance Division

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