Page 25 - JSOM Fall 2021

Exploring Tourniquet Conversion in

Simulation to Develop Concepts and Hypotheses

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John F. Kragh Jr, MD *; Tuan D. Le, MD, DrPH ; Michael A. Dubick, PhD 3

ABSTRACT
Background: Compared with those of tourniquet applica- increasingly experience conversions, these procedures are per-
tion, tourniquet conversion concepts are underdeveloped. The formed in low volume by individual caregivers.
purpose of this project was to develop tourniquet conversion
concepts and generate hypotheses. Methods: One person per- In TC, caregivers intend to minimize the risk of problems 20–24
formed 100 tests of tourniquet application and conversion. by limiting pressure and ischemia. 25–27 The mechanisms of
Testing varied by conversion types, materials, and assessments. ischemia reduction act by minimizing the duration of limb
Conversions were from improvised or Combat Application ischemia 9,11,28,29 or the length of the limb portion remaining
Tourniquets (C-A-T) to another C-A-T, a new site (with ini- ischemic. 12,30–32 Less ischemia reduces the risk of resulting
tial C-A-T only), a pneumatic Emergency and Military Tour- reperfusion complications, such as limb loss 33–37 or kidney fail-
niquet (EMT), or a pressure dressing (compression bandage or ure. 15,34,38 Conversions can ease the stress on providers man-
a roll gauze and an elastic wrap). Simulated limbs were cre- aging multiple casualties—lifesaving interventions come first;
ated using plastic bottle-based manikins, pool noodle-based conversions take place later. 39–41 Conversions are sought to
manikins, plastic pipes, glass bottles, a rain downspout, and a relieve patients of painful tourniquets, reduce care complex-
cardboard poster tube. Results: Tourniquet application, con- ity, 42,43 or downgrade emergencies by relaxing time pressures
version, and total times averaged 105, 132, and 237 seconds, on evacuation priority. 39,44 Successful conversions can benefit
respectively. Improvised tourniquet time was longer than that patients and caregivers by reducing risks, simplifying care,
of C-A-T (p ≤ .05, all three). By initial tourniquet site, the 2–3 and preserving resources. Yet TC may be lengthy, difficult, or
inches site had longer conversion and total time (p ≤ .02, both) morbid if not done or not done well. 7,10,13,33,35,45 Because most
compared with highest site. By whether initial tourniquets individuals have little experience in high-risk procedures, un-
placed were also used in conversion, total time was shorter familiar technicalities of conversions can confuse communica-
if yes (p = .05). Conversion to a pressure dressing was longer tion and risk delays.
in conversion and total time (p ≤ .02, both) compared with
conversion to a tourniquet. One wrap was short; we switched Conversion concepts include how-to advice 9,11,13,46,47 and clin-
to those longer to cover limbs better. Limb types varied for ical algorithms. 20,23,41 Such knowledge products are oriented
indentation. Conversion communications improved when we toward practical applications, such as prolonged casualty care
used abbreviations and symbols. Conclusions: This prelimi- or its teaching. However, few such products provide more
nary project simulated tourniquet conversion to develop clin- than expert opinion. Opinions are of low scientific maturity
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ical concepts and research hypotheses to build a better basis for conversion because they are insufficiently based on clinical
for later research. research or systematic study. Given that small base of empiri-
cal data, TC was prioritized in combat casualty care research.
Keywords: hemorrhage control and prevention; emergency;
simulation; risk management; device removal; ischemia; The concepts targeted for development in this study were
reperfusion which materials are suitable, which task steps are trouble-
some, and which metrics suit performances. We chose a preex-
perimental strategy using conversion devices and methods in
simulation to build a better basis for later research. The pur-
Introduction
pose of this preliminary project was to develop TC concepts
Since 2000, caregivers have increasingly used tourniquets to and generate hypotheses.
1−4
control limb-wound bleeding. Because an emergency tourni-
quet is a tool to temporarily arrest blood flow to distal wounds,
someone must later remove or exchange it for another inter- Methods
vention, such as a wound dressing, a process known as conver- We investigated TC, an underdeveloped healthcare topic. The
sion. Although authors 9–13 have recommended tourniquet exploration was in the form of a caregiver mechanically simu-
5−8
conversion (TC) typically within 2 hours, details on how this lating conversion. We assessed the conversion concepts by us-
should be done are often limited. 14−19 While trauma systems ing multiple materials, various task steps, and several methods
*Correspondence to 3698 Chambers Pass, Joint Base San Antonio Fort Sam Houston, TX 78234; or john.f.kragh.civ@mail.mil
1 Dr John F. Kragh Jr is a research scientist of hemorrhage control in the Department of Tactical Combat Casualty Care at the US Army Institute
of Surgical Research (ISR), Fort Sam Houston, TX, and an associate professor in the Department of Surgery, Uniformed Services University of
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the Health Sciences, Bethesda, MD. Dr Tuan D. Le is a general health scientist at the ISR and an adjunct professor in the Department of Epi-
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demiology and Biostatistics, University of Texas Health Science Center at Tyler, TX. Dr Michael A. Dubick was senior scientist of the Combat
Mortality Prevention Division, at the ISR before his recent death.
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