Page 126 - JSOM Fall 2019

regulates medical devices such as commercial tourniquets, TABLE 1 Examples of Material Successfully Used to Construct a Strap,
which are mass produced and sold by a variety of different Rod, and Securing Mechanism for Use in an Improvised Tourniquet
companies. Improvised tourniquets are hasty, on-the-spot Improvised Tourniquet Materials
methods of hemorrhage control made by materials that are Strap Rod Securing Mechanism
often meant to serve another purpose. Therefore, while both Cravat Stick/tree branch Cravat
types of tourniquets can achieve hemostasis, improvised tour- Bandana Wooden block Bandana
niquets are best treated as a secondary option only when no T-shirt Pens Rubber strap
commercial tourniquets are available. 8
Pant leg Pencils Kerlix
This article identifies key points in the construction of an impro- Socks Chopsticks Cord/string
vised limb tourniquet while supporting the SOF axioms of sim- Rubber strap Scissors Tape
plicity and repeatability. In other words, the technique must be Boxer shorts Wrench
simple and repeatable under stress to be successful and effective. Gym shorts Hemostat
Mouth wash bottle
General Tourniquet Characteristics Plastic sharps container
An improvised tourniquet is composed of three parts—a con-
stricting band or strap (hereafter referred to as a strap), a stick likely due to its ability to produce an even distribution of com-
or rod to tighten the band (hereafter referred to as a rod), and pressive forces and the cravat provides an ideal length for the
a means of securing the rod. The ultimate goal of a tourniquet material. If another material is used (such as clothing), it is
is to arrest arterial blood flow and thus stop distal bleeding. 9 advisable to look for or cut out a strip of cloth that mimics
a cravat. Ultimately, with ample experience and training, any
To accomplish this, the compressive force must be greater material might be used without needing to adapt its shape.
than the systolic blood pressure and remain above this level
throughout the resuscitation process. Studies on orthopedic In addition to the type of material used for the strap, the width
patients with normal blood pressure (normotensive) under- of the strap is important. The compressive force required to
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going elective surgeries suggest a compressive force that cor- achieve arterial occlusion is proportional to the circumference
relates with a pressure of approximately 200mmHg or higher of the limb and inversely proportional to the width of the
is needed. However, trauma patients requiring a tourniquet strap. Commercial tourniquets have made use of this rela-
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are generally not normotensive and are prone to changes in tionship to promote wide tourniquet straps, under the guise of
blood pressure throughout the resuscitation process. As a needing less pressure and potentially being more efficacious.
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result, slightly lower compressive forces may initially be ad- While this may be true from a physiologic standpoint, several
equate, but consideration should be given to ensure that the studies have shown nominal improvement in efficacy beyond
tourniquet pressure remains high enough as the patient’s blood a 2cm-wide commercial strap. 17,18 Strap widths ranging from
pressure increases with successful resuscitation. Frequent reas- 2cm to 10cm will provide an equal distribution of force and
sessment of an improvised tourniquet is even more important are generally adequate for most improvised tourniquets. A
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than with a commercial tourniquet. narrower strap (especially those less than 2cm wide) focuses
the compressive force over too small an area and leads to ad-
ditional complications, such as ischemia and destruction of
Improvised Tourniquet Straps
the tissue directly under the tourniquet itself. Another noted
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Historically, belts were considered adequate for the construc- challenge encountered with narrow tourniquets is a higher
tion of an improvised tourniquet as they were common and level of pain. 14,21 Additionally, while twisting the windlass rod,
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could readily be used to create a circumferential compressive skin can be pulled into the strap if the strap is too narrow.
force. While preliminary studies suggested their merit, subse-
quent experience has demonstrated a high rate of failure when Improvised Tourniquet Rods
belts are used as a tourniquet. Implementation of a windlass
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mechanism with rigid materials commonly found with civilian The rod is a critical part of the tourniquet design. Not using a
belts can prove very difficult. Although using a belt for the rod is associated with nearly universal failure as the pressure
strap remains of interest and may have some merit, we rec- compression created is well below the expected systolic arte-
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ommend against their use as a first choice when constructing rial pressure. In fact, it has been hypothesized that the failure
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an improvised tourniquet. Instead, an improvised tourniquet of including a rod into any of improvised tourniquets made
should optimally mimic the common characteristics of com- after the Boston Marathon bombing in 2013 may have been
mercially designed tourniquets. why none were deemed effective. 22
Cotton-based materials can be a very practical material for a A windlass mechanism (as the term is used in medical and mil-
strap in an improvised tourniquet. 13–15 Most articles of clothing itary parlance) achieves its results by including a mechanical
(shirts, pants, shorts, socks), regardless of material, can be con- arm, the rod, through which torque can be applied to the strap
figured into a successful strap (Table 1). Additionally, triangular and thereby increase the strap’s constrictive tension. The rod
cravat bandages common in most first aid kits make for an ex- must be hard and strong enough to withstand the force ex-
cellent strap material for an improvised tourniquet and can serve erted back upon it without bending or breaking. For this rea-
as the example for the standard in other available materials. son, commercial tourniquets generally use a rod created out of
solid metal or plastic, with the latter being more prone to bend-
A cravat, no matter if synthetically produced or cotton, is an ing and breaking. In an ideal situation, a solid piece of metal
effective and reliable material for the lower extremities, most would be used to create the rod for an improvised tourniquet.

124 | JSOM Volume 19, Edition 3 / Fall 2019